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  1. //code pfs
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4. typedef long long ll;
  5. const int MAXN = 1e5 + 7;
  6. string s;
  7. ll n, k, ans;
  8.  
  9. int main() {
  10.     ios_base::sync_with_stdio(0);
  11.     cout.tie(0);
  12.     cin.tie(0);
  13.     //freopen("input.inp", "r", stdin);freopen("output.out", "w", stdout);
  14.     cin >> k >> s;
  15.     n = s.size();
  16.     s = ' ' + s;  
  17.     vector<ll> freq(n + 1, 0);
  18.     freq[0] = 1;
  19.     ll p = 0;
  20.     for (int i = 1; i <= n; i++) {
  21.         if (s[i] == '1') p++;
  22.         if (p >= k) ans += freq[p - k];
  23.         freq[p]++;
  24.     }
  25.     cout << ans;
  26.  
  27. }
Success #stdin #stdout 0.01s 5264KB
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Standard output is empty
https://ideone.com/zA3iEo
language:
C++14 (gcc 8.3)
created:
20 hours ago
visibility:
public

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