Submission #1794753

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Source Code Expand

#include<bits/stdc++.h>

using namespace std;

using vi = vector< int >;
using vii = vector< vi >;

const int mod = 1e9 + 7;

int main()
{
  int N, X;
  string S;

  cin >> N >> X;
  cin >> S;

  vii dp(N + 2, vi(X + 1));
  dp[0][0] = 1;
  for(int i = 0; i < N; i++) {
    vii dp2(N + 2, vi(X + 1));
    for(int l = 0; l < 10; l++) {
      if(S[i] != '?' && S[i] - '0' != l) continue;
      for(int j = N; j >= 0; j--) {
        for(int k = X; k >= 0; k--) {
          if(l == 2) {
            if(j % 2 == 0) (dp2[j + 1][k] += dp[j][k]) %= mod;
            else(dp2[1][k] += dp[j][k]) %= mod;
          } else if(l == 5 && j % 2 == 1) {
            (dp2[j + 1][min(X, k + (j + 1) / 2)] += dp[j][k]) %= mod;
          } else {
            (dp2[0][k] += dp[j][k]) %= mod;
          }
        }
      }
    }
    dp.swap(dp2);
  }

  int ret = 0;
  for(int i = 0; i <= N; i++) {
    (ret += dp[i][X]) %= mod;
  }
  cout << ret << endl;
}

Submission Info

Judge Result