Time Limit: 1 Sec

Memory Limit: 256 MB

题目连接

http://acm.hdu.edu.cn/contests/contest_showproblem.php?pid=1001&cid=621

Description

Input

1
7 7
1 2 3 4 5 6 7
1 4
1 5
4 5
2 3
2 6
3 6
2 7

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>using namespace std;const int N=200100;
long long a[N],ans;
int n,m,T,cnt,ok[N],vis[N],pre[N],nxt[N],to[N],tot[N],col;
vector<int> s[N];
queue<int> q;void dfs(int x,int fa)
{s[col].push_back(x);ok[x]=0;for(int p=pre[x];p!=-1;p=nxt[p]){if((!vis[p])||(!ok[to[p]])) continue;if(p==(fa^1)) continue;dfs(to[p],p);}
}
void makeedge(int x,int y)
{to[cnt]=y;nxt[cnt]=pre[x];pre[x]=cnt++;to[cnt]=x;nxt[cnt]=pre[y];pre[y]=cnt++;
}int main()
{scanf("%d",&T);while(T--){memset(tot,0,sizeof(tot));memset(pre,-1,sizeof(pre));memset(ok,1,sizeof(ok));memset(vis,1,sizeof(vis));ans=0LL;cnt=0;scanf("%d%d",&n,&m);for(int i=1;i<=n;i++){scanf("%I64d",&a[i]);}for(int i=0;i<m;i++){int x,y;scanf("%d%d",&x,&y);tot[x]++;tot[y]++;makeedge(x,y);}while(!q.empty()) q.pop();for(int i=1;i<=n;i++){if(tot[i]<2){q.push(i);}}while(!q.empty()){int x=q.front();q.pop();ok[x]=0;for(int p=pre[x];p!=-1;p=nxt[p]){vis[p]=0;tot[x]--;tot[to[p]]--;if(ok[to[p]]&&tot[to[p]]<2){q.push(to[p]);}}}col=0;for(int i=1;i<=n;i++){col++;s[col].clear();if(ok[i]){dfs(i,cnt+10);if(s[col].size()%2==1){for(int j=0;j<s[col].size();j++){ans+=a[s[col][j]];}}}}printf("%I64d\n",ans);}return 0;
}