PAT T1022 Werewolf

暴力搜索加剪枝~

#include<bits/stdc++.h>
using namespace std;
const int maxn=;
int a[maxn];
bool visit[maxn];
vector<int> path,tmp;
int N,M,L,cnt=;
void dfs (int v) {
    if (tmp.size()==M) {
        int liecnt=,liewolf=;
        for (int i=;i<=N;i++) {
            if (a[i]<&&visit[abs(a[i])]==false) {
                liecnt++;
                if (visit[i]==true) liewolf++;
            }
            else if (a[i]>&&visit[abs(a[i])]==true) {
                liecnt++;
                if (visit[i]==true)  liewolf++;
            }
        }
        if (liecnt==L&&liewolf>=&&liewolf<M&&cnt==) path=tmp,cnt++;
        return;
    }
    if (tmp.size()+v<L) return;
    v--;
    while (v>=) {
        visit[v]=true;
        tmp.push_back(v);
        dfs (v);
        visit[v]=false;
        tmp.pop_back();
        v--;
    }
}
int main () {
    scanf ("%d %d %d",&N,&M,&L);
    for (int i=;i<=N;i++) {
        scanf ("%d",&a[i]);
    }
    dfs (N+);
    if (path.size()==) {
        printf ("No Solution");
        return ;
    }
    for (int i=;i<path.size();i++) {
        if (i!=) printf (" ");
        printf ("%d",path[i]);
    }
    return ;
}