UVA 10128 Queue

大意略。

思路：没有思路，特别是许多情况很难想清楚，于是参考了网上的资料。

#include <iostream>#include <cstdlib>#include <cstdio>#include <cstring>#include <string>using namespace std;typedef long long LL;LL d[14][14][14];int N, P, R;void init(){memset(d, 0, sizeof(d));}void read_case(){init();scanf("%d%d%d", &N, &P, &R);}int dp(){d[1][1][1] = 1;for(int i = 2; i <= N; i++){for(int j = 1 ; j <= P; j++){for(int k = 1; k <= R; k++){d[i][j][k] = d[i-1][j-1][k] + d[i-1][j][k-1] + (i-2) * d[i-1][j][k];}}}return d[N][P][R];}void solve(){read_case();LL ans = dp();printf("%lld\n", ans);}int main(){int T;scanf("%d", &T);while(T--){solve();}return 0;}