zstu.4019.排队购票(多维dp)

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<algorithm>
 4 using namespace std;
 5 const int N = 30 + 5 ;
 6 int dp[N][N];
 7 int T  ;
 8 int n,m;
 9 int main()
10 {
11     //freopen ("a.txt" , "r" , stdin ) ;
12     scanf("%d",&T);
13     while( T --)
14     {
15         memset(dp,0,sizeof(dp));
16         scanf("%d%d",&n,&m);
17         if(n < m ) {
18             puts ("0") ;
19             continue ;
20         }
21         for(int i = 0 ; i <= n ; i++)
22         {
23             for(int j = 0 ; j <= max(i,m) ; j ++)
24             {
25                 if(i == 0 )  dp[i][j] = 0 ;
26                 else if(j == 0 && i != 0 )dp[i][j] = 1 ;
27                 else
28                 {
29                     dp[i][j] = dp[i-1][j];
30                     if(i > j-1) dp[i][j] += dp[i][j-1];
31                 }
32             }
33         }
34        
35         printf("%d\n",dp[n][m]);
36     }
37     return 0 ;
38 }