HDU 1466 计算直线的交点数

 1 #include<stdio.h>
 2 #include<string.h>
 3 #define N 21
 4 #define M N*(N-1)/2
 5 int dp[N][M];
 6 int main()
 7 {
 8     int i, j, n, k;
 9     dp[0][0] = 1;dp[1][0] = 1;
10     for(n = 2; n <= N; n++){
11         for(i = 0; i < n; i++){
12             for(j = 0; j <= i * (i-1) / 2; j++){
13                 if(dp[i][j] == 1){
14                     dp[n][i * (n-i) + j] = 1;
15                 }
16             }
17         }
18     }
19     while(~scanf("%d", &n))
20     {
21         printf("0");
22         for(i=1; i<=n*(n-1)/2; i++){
23             if(dp[n][i] == 1){
24                 printf(" %d", i);
25             }
26         }
27         printf("\n");
28     }
29     return 0;
30 }