#include <iostream> // 计算一个数的各位数字之和 int digitSum(int num) { int sum = 0; while (num > 0) { sum += num % 10; num /= 10; } return sum; } int main() { int n; std::cin >> n; int count = 0; // 遍历 1 到 n 的所有数 for (int i = 1; i <= n; ++i) { if (digitSum(i) == 13) { ++count; } } std::cout << count << std::endl; return 0; } /************************************************************** Problem: 1511 User: panyuchen Language: C++ Result: Accepted Time:102 ms Memory:2072 kb ****************************************************************/