题解 | #挑7#
挑7
https://www.nowcoder.com/practice/ba241b85371c409ea01ac0aa1a8d957b
#include <iostream> #include <string> using namespace std; int main() { string str; int num,cnt = 0; cin >> num; for (int i = 7; i <= num; ++i) { if (i % 7 == 0) { cnt++; continue; } str = to_string(i); for (char x : str) { if (x == '7') { cnt++; break; } } } cout << cnt << endl; return 0; }