AtCoder Regular Contest 118 A - Tax Included Price

周期性の回答を実装してみた。

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
  int64_t t, N;
  cin >> t >> N;

  int64_t ret = 0;
  int64_t s = 100 + t;
  int64_t r = 0;
  int c = 0;

  vector<bool> temp(s,true);

  rep(i, 100) {
    temp[s * i / 100] = false;
  }

  r = (N - 1) / t;
  ret = r * s;
  c = (N - 1)  % t;
  

  rep(i, s) {
    if (temp[i]) {
      if (!c--) {
        ret += i;
        break;
      }
    }
  }

  cout << ret << endl;
}