Problem A number is called lucky if the sum of its digits, as well as the sum of the squares of its digits is a prime number. How many numbers between A and B are lucky?
Input: The first line contains the number of test cases T. Each of the next T lines contains two integers, A and B.
Output: Output T lines, one for each case containing the required answer for the corresponding case.
Constraints:
1 <= T <= 10000
1 <= A <= B <= 10^18Sample Input:
2
1 20
120 130
Sample Output:
4
1
Explanation: For the first case, the lucky numbers are 11, 12, 14, 16. For the second case, the only lucky number is 120.
如果我们使用蛮力,问题就非常简单,但是运行时间非常关键,以至于我的程序在大多数测试用例中都失败了。我目前的想法是通过将之前的总和存储在一个临时数组中来使用动态规划,例如:
sum_digits(10) = 1 -> sum_digits(11) = sum_digits(10) + 1
同样的想法适用于和平方,但计数器等于奇数。不幸的是,它仍然失败了 10 个测试用例中的 9 个,这让我认为必须有更好的方法来解决它。任何想法将不胜感激。
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <cassert>
#include <bitset>
using namespace std;
bool prime_table[1540] = {
0, 0, 1, 1, 0, 1, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 1, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 1, 0, 0, 0, 1, 0,
1, 0, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0
};
unsigned num_digits(long long i) {
return i > 0 ? (long) log10 ((double) i) + 1 : 1;
}
void get_sum_and_sum_square_digits(long long n, int& sum, int& sum_square) {
sum = 0;
sum_square = 0;
int digit;
while (n) {
digit = n % 10;
sum += digit;
sum_square += digit * digit;
n /= 10;
}
}
void init_digits(long long n, long long previous_sum[], const int size = 18) {
int current_no_digits = num_digits(n);
int digit;
for (int i = 0; i < current_no_digits; ++i) {
digit = n % 10;
previous_sum[i] = digit;
n /= 10;
}
for (int i = current_no_digits; i <= size; ++i) {
previous_sum[i] = 0;
}
}
void display_previous(long long previous[]) {
for (int i = 0; i < 18; ++i) {
cout << previous[i] << ",";
}
}
int count_lucky_number(long long A, long long B) {
long long n = A;
long long end = B;
int sum = 0;
int sum_square = 0;
int lucky_counter = 0;
get_sum_and_sum_square_digits(n, sum, sum_square);
long long sum_counter = sum;
long long sum_square_counter = sum_square;
if (prime_table[sum_counter] && prime_table[sum_square_counter]) {
lucky_counter++;
}
long long previous_sum[19] = {1};
init_digits(n, previous_sum);
while (n < end) {
n++;
if (n % 100000000000000000 == 0) {
previous_sum[17]++;
sum_counter = previous_sum[17] + previous_sum[18];
sum_square_counter = previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18];
previous_sum[16] = 0;
previous_sum[15] = 0;
previous_sum[14] = 0;
previous_sum[13] = 0;
previous_sum[12] = 0;
previous_sum[11] = 0;
previous_sum[10] = 0;
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 10000000000000000 == 0) {
previous_sum[16]++;
sum_counter = previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[15] = 0;
previous_sum[14] = 0;
previous_sum[13] = 0;
previous_sum[12] = 0;
previous_sum[11] = 0;
previous_sum[10] = 0;
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 1000000000000000 == 0) {
previous_sum[15]++;
sum_counter = previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[14] = 0;
previous_sum[13] = 0;
previous_sum[12] = 0;
previous_sum[11] = 0;
previous_sum[10] = 0;
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 100000000000000 == 0) {
previous_sum[14]++;
sum_counter = previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[13] = 0;
previous_sum[12] = 0;
previous_sum[11] = 0;
previous_sum[10] = 0;
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 10000000000000 == 0) {
previous_sum[13]++;
sum_counter = previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[12] = 0;
previous_sum[11] = 0;
previous_sum[10] = 0;
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 1000000000000 == 0) {
previous_sum[12]++;
sum_counter = previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[11] = 0;
previous_sum[10] = 0;
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 100000000000 == 0) {
previous_sum[11]++;
sum_counter =
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[10] = 0;
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 10000000000 == 0) {
previous_sum[10]++;
sum_counter =
previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[9] = 0;
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 1000000000 == 0) {
previous_sum[9]++;
sum_counter =
previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[8] = 0;
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 100000000 == 0) {
previous_sum[8]++;
sum_counter =
previous_sum[8] + previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[7] = 0;
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 10000000 == 0) {
previous_sum[7]++;
sum_counter =
previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[7] * previous_sum[7] +
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[6] = 0;
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 1000000 == 0) {
previous_sum[6]++;
sum_counter =
previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[6] * previous_sum[6] +
previous_sum[7] * previous_sum[7] +
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[5] = 0;
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 100000 == 0) {
previous_sum[5]++;
sum_counter = previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[5] * previous_sum[5] +
previous_sum[6] * previous_sum[6] +
previous_sum[7] * previous_sum[7] +
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[4] = 0;
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 10000 == 0) {
previous_sum[4]++;
sum_counter =
previous_sum[4] + previous_sum[5] +
previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[4] * previous_sum[4] +
previous_sum[5] * previous_sum[5] +
previous_sum[6] * previous_sum[6] +
previous_sum[7] * previous_sum[7] +
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[3] = 0;
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 1000 == 0) {
previous_sum[3]++;
sum_counter =
previous_sum[3] + previous_sum[4] + previous_sum[5] +
previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[3] * previous_sum[3] +
previous_sum[4] * previous_sum[4] +
previous_sum[5] * previous_sum[5] +
previous_sum[6] * previous_sum[6] +
previous_sum[7] * previous_sum[7] +
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[2] = 0;
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 100 == 0) {
previous_sum[2]++;
sum_counter =
previous_sum[2] + previous_sum[3] + previous_sum[4] + previous_sum[5] +
previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[2] * previous_sum[2] +
previous_sum[3] * previous_sum[3] +
previous_sum[4] * previous_sum[4] +
previous_sum[5] * previous_sum[5] +
previous_sum[6] * previous_sum[6] +
previous_sum[7] * previous_sum[7] +
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[1] = 0;
previous_sum[0] = 0;
}
else if (n % 10 == 0) {
previous_sum[1]++;
sum_counter =
previous_sum[1] + previous_sum[2] + previous_sum[3] + previous_sum[4] + previous_sum[5] +
previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] +
previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] +
previous_sum[16] + previous_sum[17] + previous_sum[18];
sum_square_counter =
previous_sum[1] * previous_sum[1] +
previous_sum[2] * previous_sum[2] +
previous_sum[3] * previous_sum[3] +
previous_sum[4] * previous_sum[4] +
previous_sum[5] * previous_sum[5] +
previous_sum[6] * previous_sum[6] +
previous_sum[7] * previous_sum[7] +
previous_sum[8] * previous_sum[8] +
previous_sum[9] * previous_sum[9] +
previous_sum[10] * previous_sum[10] +
previous_sum[11] * previous_sum[11] +
previous_sum[12] * previous_sum[12] +
previous_sum[13] * previous_sum[13] +
previous_sum[14] * previous_sum[14] +
previous_sum[15] * previous_sum[15] +
previous_sum[16] * previous_sum[16] +
previous_sum[17] * previous_sum[17] +
previous_sum[18] * previous_sum[18];
previous_sum[0] = 0;
}
else {
sum_counter++;
sum_square_counter += ((n - 1) % 10) * 2 + 1;
}
// get_sum_and_sum_square_digits(n, sum, sum_square);
// assert(sum == sum_counter && sum_square == sum_square_counter);
if (prime_table[sum_counter] && prime_table[sum_square_counter]) {
lucky_counter++;
}
}
return lucky_counter;
}
void inout_lucky_numbers() {
int n;
cin >> n;
long long a;
long long b;
while (n--) {
cin >> a >> b;
cout << count_lucky_number(a, b) << endl;
}
}
int main() {
inout_lucky_numbers();
return 0;
}
最佳答案
由于 A-B 可能是 10^18 值的范围,因此无论如何优化,您都无法及时从 A 循环到 B。让我们试着找出一种方法来做到这一点,而不涉及具体考虑所有这些数字......
首先,让我们将问题简化为找到 1 和 E 之间的幸运数字,并将其称为 lucky(E)。整个问题的答案很简单,幸运(B)-幸运(A-1)。
现在让我们逐位构建这样一个幸运数字。假设我们已经在这个数字上放置了几位数字,需要继续。我们已经放置了哪些数字重要吗?不!我们只需要知道以下内容:
这将是动态规划中所谓的状态。
让我们忽略 10^18,因为它是输入中唯一有 19 位数字的数字,而且它并不幸运。请注意,E 最多可能有 18 位数字,因此我们有 19 种可能的 n(从 0 到 18),162 (18 * 9 + 1) 种可能的 s,和 1459 (18 * 81 + 1) 种可能的 sq。这留给我们最多 500 万个搜索空间,这比搜索 10^18 个数字的匹配要小得多。
因此,让我们将 F(n, s, sq) 定义为“我们可以通过多少种方式将数字添加到具有此类属性的数字中以获得幸运数字”(感谢 kilotaras 的改写)。基本情况是当 n 等于 E 中的位数时:如果 s 和 sq 是素数,则 F(N, s, s_sq) 为 1,否则为 0。对于其他可能性,进行可能的转换并递归调用 F,注意不要让您正在构造的数字超过 E。
通过这种方式,我们可以将 lucky(E) 定义为 F(0, 0, 0)。
完成后,请记住记住已计算输入/输出的函数。
编辑:这有点旧,但这里是 lucky 函数的示例实现,我相信它是正确的。请注意,与上面的解释相反,n 在代码中下降了,因为以这种方式编写代码要容易得多。
long long dp[20][163][1460];
bool calc[20][163][1460];
int digits[20];
int digit_cnt;
// The last argument (eq) is used to avoid going over E
long long F(int n, int s, int sq, bool eq) {
// Base cases
if (!eq && calc[n][s][sq]) return dp[n][s][sq];
if (n == 0) return (prime_table[s] && prime_table[sq]);
long long resp = 0;
// Test all possibilities for the next digit
for (int d = 0; d < 10; d++) {
if (!eq || digits[n-1] > d) {
resp += F(n-1, s+d, sq + d*d, false);
}
// If the number formed so far is exactly equal to E
// we will go over E if we pick a larger
// digit than digits[n-1].
// So we have to take care if eq == true
else if (digits[n-1] == d) {
resp += F(n-1, s+d, sq + d*d, true);
}
else break;
}
// Note that computations that have eq set to true
// can't be used in other calculations of F(), as they depend on E.
if (!eq) {
calc[n][s][sq] = true;
dp[n][s][sq] = resp;
}
return resp;
}
long long lucky(long long E) {
long long tE = E;
digit_cnt = 0;
while (tE) {
digits[digit_cnt++] = tE % 10;
tE /= 10;
}
return F(digit_cnt, 0, 0, true);
}
关于c++ - 如何优化动态规划?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/11045090/
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