HDU-5952-Counting Cliques（搜索剪枝）

鏈接：http://acm.hdu.edu.cn/showproblem.php?pid=5952

題意：給定n,m,k-----n個點m條邊的無向圖，求k個點的完全圖個數

#include <bits/stdc++.h>
//#pragma comment(linker, "/STACK:1024000000,1024000000")
using namespace std;
#define INF 0x3f3f3f3f
#define LL long long
#define bug cout<<"bug"<<endl
const int MAXN = 107;
const int MAXM = 20007;
const int MOD = 1e9 + 9;
#define P 0x000000ff
using namespace std;
int link[MAXN][MAXN];
int edge[MAXN][MAXN];
bool vis[MAXN];
int DFS(int u, int k, int node[])
{
    if(k<=0)return 1;
    int temp[MAXN],ans=0;
    for(int i=1; i<=node[0]-k+1; ++i)
    {
        int v=node[i];
        temp[0]=0;
        for(int j=i+1; j<=node[0]; ++j)
            if(link[v][ node[j] ])
                temp[ ++temp[0] ]=node[j];
        if(temp[0]>=k-1)ans+=DFS(v,k-1,temp);
    }
    return ans;
}
int main()
{
    int T,n,m,k;
    scanf("%d",&T);
    while(T--)
    {
        int u,v;
        memset(link,0,sizeof(link));
        memset(edge,0,sizeof(edge));
        memset(vis,false,sizeof(vis));

        scanf("%d%d%d",&n,&m,&k);
        for(int i=0; i<m; ++i)
        {
            scanf("%d%d",&u,&v);
            link[u][v]=link[v][u]=1;
            edge[u][ ++edge[u][0] ]=v;
            edge[v][ ++edge[v][0] ]=u;
        }
        int ans=0;
        int temp[MAXN];
        temp[0]=0;
        for(int i=1; i<=n; ++i)
        {
            vis[i]=1;
            temp[0]=0;
            for(int j=1; j<=edge[i][0]; ++j)
                if(!vis[edge[i][j]])temp[++temp[0]]=edge[i][j];
            ans+=DFS(i,k-1,temp);
        }
        printf("%d\n",ans);
    }
    return 0;
}
/*
3
4 3 2
1 2
2 3
3 4
5 9 3
1 3
1 4
1 5
2 3
2 4
2 5
3 4
3 5
4 5
6 15 4
1 2
1 3
1 4
1 5
1 6
2 3
2 4
2 5
2 6
3 4
3 5
3 6
4 5
4 6
5 6
*/