Submission #1371986

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Source Code Expand

#include<bits/stdc++.h>
const int P = 1e9 + 7;
int dp[3005][3005][2];

int main() {
  if(fopen("input.txt","r")) {
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
  }

  int N, M; scanf("%d%d", &N, &M);
  for(int i = 1;i <= N; ++i)
    dp[0][i][0] = 1;
  dp[0][0][1] = 1;
  for(int i = 0;i < M; ++i) {
    for(int j = 0;j <= N; ++j) {
      for(int k = 0;k < 2; ++k) {
	if(!dp[i][j][k]) continue;
	if(j) {
	  (dp[i+1][j-1][k|(j==1)] += dp[i][j][k]) %= P;
	  (dp[i+1][j][k|(j==1)] += dp[i][j][k]) %= P;
	}
	if(N-j) {
	  (dp[i+1][j+1][k] += dp[i][j][k]) %= P;
	  (dp[i+1][j][k] += dp[i][j][k]) %= P;
	}
      }
    }
  }

  int ans = 0;
  for(int i = 0;i <= N; ++i)
    (ans += dp[M][i][1]) %= P;
  printf("%d", ans);
  
  return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:7:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
     freopen("input.txt","r",stdin);
                                   ^
./Main.cpp:8:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
     freopen("output.txt","w",stdout);
                                     ^
./Main.cpp:11:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   int N, M; scanf("%d%d", &N, &M);
                                  ^

Judge Result