hdu 3339 In Action spfa最短路+01背包

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<cmath>
#include<map>
#include<cassert>
#include<cstdio>
#include<iomanip>
#include<queue>
#include<stack>
using namespace std;
const int maxn=111;
const int maxc=1001000;
const int inf=0x3f3f3f3f;
struct zz
{
    int from;
    int to;
    int cost;    
}zx,tz;
int T,n,m,sum,total,half,need;
vector<zz>g[maxn];
queue<int>q;
int get[maxn];
int power[maxn];
bool vis[maxn];
int can[maxc];

void spfa()
{
    while(!q.empty())
    {
        q.pop();
    }
    for(int i=1;i<=n;i++)
    {
        get[i]=inf;
    }
    memset(vis,false,sizeof(vis));
    q.push(0);
    vis[0]=true;
    get[0]=0;
    power[0]=0;
    int now;
    int to;
    int cost;
    while(!q.empty())
    {
        now=q.front();
        q.pop();
        for(int i=0;i<g[now].size();i++)
        {
            to = g[now][i].to;
            cost = get[now] + g[now][i].cost;
            if( cost < get[to] )
            {
                get[to]=cost;
                if(!vis[to])
                {
                    vis[to]=true;
                    q.push(to);
                }
            }
        }       
        vis[now]=false;
    }
    sum=0;
    total=0;
    for(int i=1;i<=n;i++)
    {
        if(get[i]!=inf)
        {
            total+=power[i];
            sum+=get[i];
        }
    }  
    return ;
}

bool disable()
{
    if( total < half ) 
    {
        return false;
    }      
    memset(can,0,sizeof(int)*(sum+maxn));
    int temp;
    for(int j=1;j<=n;j++)
    {
        for(int i=sum;i>=get[j];i--)
        {        
            can[i]=max(can[i],can[i-get[j]] + power[j]);
        }
    }
    for(int i=0;i<=sum;i++)
    {
        if(can[i] >=half)
        {
            need=i;
            return true;
        }
    }
    assert(false);
}

int main()
{
    cin>>T;
    while(T--)
    {
        cin>>n>>m;      
        for(int i=0;i<=n;i++)
        {
            g[i].clear();
        }
        for(int i=1;i<=m;i++)    
        {
            cin>>zx.from>>zx.to>>zx.cost;   
            g[zx.from].push_back(zx);
            swap(zx.from,zx.to);
            g[zx.from].push_back(zx);
        }
        total=0;
        for(int i=1;i<=n;i++)
        {
            cin>>power[i];  
            total+=power[i];
            half=total/2;
            half++;  
        }
        spfa();
        if(!disable())
        {
            cout<<"impossible"<<endl;
        }
        else
        {
            cout<<need<<endl;
        }     
    }
    return 0;
}