PAT T1021 Safe Fruit

暴力搜索加剪枝~

看的人好多...更新一下：

这道题的正解应该是求最大团之类的...暴力搜索是拿不到分的，我用了好几种奇怪的技巧用爆搜卡掉了。。。

#include<bits/stdc++.h>
using namespace std;
const int maxn=;
const int inf=1e9;
int g[maxn][maxn];
int c[maxn];
int N,M;
int mincost=1e9;
int cost=;
int flag;
int tle=;
int ans=;
bool visit[maxn];
vector<int> path,tmp;
void dfs (int v,int direction) {
    tle++;
    if (tle>1e5) return;
    if (tmp.size()>path.size()) {
        path=tmp;
        mincost=cost;
    }
    else if (tmp.size()==path.size()&&cost<mincost) {
        path=tmp;
        mincost=cost;
    }
    if (direction==) {
        v++;
        while (v<=) {
            flag=;
            if (c[v]==) {
                v++;
                continue;
            }
                for (int j=;j<tmp.size();j++)
                if (g[v][tmp[j]]==) {
                    flag++;
                    break;
                }
            if (flag==) {
                tmp.push_back(v);
                visit[v]=true;
                cost+=c[v];
                dfs (v,);
                tmp.pop_back();
                visit[v]=false;
                cost-=c[v];
            }
            v++;
        }
    }
    else {
        v--;
        while (v>=) {
            flag=;
            if (c[v]==) {
                v--;
                continue;
            }
            for (int j=;j<tmp.size();j++)
            if (g[v][tmp[j]]==) {
                flag++;
                break;
            }
            if (flag==) {
                tmp.push_back(v);
                visit[v]=true;
                cost+=c[v];
                dfs (v,);
                tmp.pop_back();
                visit[v]=false;
                cost-=c[v];
            }
            v--;
        }
    }
}
int main () {
    scanf ("%d %d",&M,&N);
    int u,v;
    for (int i=;i<M;i++)
    scanf ("%d %d",&u,&v),g[u][v]=g[v][u]=;
    for (int i=;i<=N;i++) {
        scanf ("%d %d",&u,&v);
        c[u]=v;
        if (v>) ans++;
    }
    if (ans!=) dfs (,);
    else dfs (,);
    printf ("%d\n",path.size());
    sort (path.begin(),path.end());
    for (int i=;i<path.size();i++) {
        if (i!=) printf (" ");
        printf ("%03d",path[i]);
    }
    printf ("\n%d",mincost);
    return ;
}