Luo Gu P1130 red card

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Problem-solving ideas:

A DP of the matrix, f [i] [j] denotes the i-th row of the answer column j

AC Code:

 1 #include<iostream>
 2 #include<cstdio>
 3 
 4 using namespace std;
 5 
 6 int n,m,a[2001][2001],f[2001][2001],ans = 99999999;
 7 
 8 int main() {
 9     scanf("%d%d",&m,&n);
10     for(int i = 1;i <= n; i++)
11         for(int j = 1;j <= m; j++)
12             scanf("%d",&a[i][j]);
13     for(int i = 1;i <= m; i++)
14         for(int j = 1;j <= n; j++) {
15             if(j == 1)
16                 f[j][i] = min(f[j][i-1],f[n][i-1]) + a[j][i];
17             else
18                 f[j][i] = min(f[j][i-1],f[j-1][i-1]) + a[j][i];
19         }
20     for(int i = 1;i <= n; i++)
21         ans = min(f[i][m],ans);
22     printf("%d",ans);     
23     return 0;
24 }