HDU 3339 In Action

#include <iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
#define M 10005
#define INF 1<<29
#define N 105
using namespace std;
int n,cnt,head
,dis
,p
,vis
,dp[M];
struct edge{
    int v,w,next;
}e[M*2];
void init(){
    cnt=0;
    memset(head,-1,sizeof(head));
}
void addedge(int u,int v,int w){
    e[cnt].v=v;e[cnt].w=w;e[cnt].next=head[u];head[u]=cnt++;
    e[cnt].v=u;e[cnt].w=w;e[cnt].next=head[v];head[v]=cnt++;
}
void SPFA(int u){
    queue<int>q;
    int i,v,w;
    for(i=1;i<=n;i++){
        dis[i]=INF;
        vis[i]=0;
    }
    q.push(u);
    while(!q.empty()){
        u=q.front();
        q.pop();
        vis[u]=0;
        for(i=head[u];i!=-1;i=e[i].next){
            v=e[i].v;
            w=e[i].w;
            if(dis[u]+w<dis[v]){
                dis[v]=dis[u]+w;
                if(!vis[v]){
                    vis[v]=1;
                    q.push(v);
                }
            }
        }
    }
}
int main()
{
    int t,m,u,v,w,i,sum,tmp,total;
    scanf("%d",&t);
    while(t--){
        init();
        scanf("%d%d",&n,&m);
        while(m--){
            scanf("%d%d%d",&u,&v,&w);
            addedge(u,v,w);
        }
        sum=0;
        for(i=1;i<=n;i++){
            scanf("%d",&p[i]);
            sum+=p[i];
        }
        SPFA(0);
        sum=sum/2+1;
        total=0;
        for(i=1;i<=n;i++)
        if(dis[i]!=INF)
        total+=dis[i];
        memset(dp,0,sizeof(dp));
        for(i=1;i<=n;i++){
            for(v=total;v>=dis[i];v--){
                dp[v]=max(dp[v],dp[v-dis[i]]+p[i]);
            }
        }
        for(i=0;i<=total;i++)
        if(dp[i]>=sum)
        break;
        if(i<=total)
        printf("%d\n",i);
        else
        printf("impossible\n");

    }
    return 0;
}
/*
100
2 3
0 2 9
2 1 3
1 0 2
3
2
3 3
0 1 1
0 2 2
0 3 3
2 3 5
5 5
0 1 8
0 2 1
0 3 1
0 4 1
0 5 1
4 1 1 1 2

*/