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#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <cmath>#include <stack>#include <queue>#include <vector>#include <map>#include <string>#include <iostream>using
namespace std;int
n;const
int INF=0xfffffff;struct
edge{ int
val;int
to;int
next;}e[111111];int
len;int
head[11111];void
add(int
from,int
to,int
val){ e[len].to=to;e[len].val=val;e[len].next=head[from];head[from]=len++;}int
dis[11111];int
spfa(int
x){ int
vis[11111]; for(int
i=1;i<=n;i++) vis[i]=0; for(int
i=1;i<=n;i++) dis[i]=INF; vis[x]=1; dis[x]=0; queue<int> q; q.push(x); int
cnt[11111]={0}; cnt[x]=1; while(!q.empty()){ int
cur=q.front(); q.pop();vis[cur]=0; for(int
i=head[cur];i!=-1;i=e[i].next){ int
cc=e[i].to; if(dis[cc]>dis[cur]+e[i].val){ dis[cc]=dis[cur]+e[i].val; if(!vis[cc]){ cnt[cc]++;if(cnt[cc]>n) return
0; q.push(cc); vis[cc]=1; } } } } return
1;}int
main(){ int
m,l; while(scanf("%d%d%d",&n,&m,&l)!=EOF){ len=0;memset(head,-1,sizeof(head)); for(int
i= 0;i<m;i++){ int
a,b,c;scanf("%d%d%d",&a,&b,&c); if(a>b) {int
t=a;a=b;b=t;} add(a,b,c); } for(int
i=0;i<l;i++){ int
a,b,c;scanf("%d%d%d",&a,&b,&c); if(a<b){int
t=a;a=b;b=t;}; add(a,b,-c); } if(!spfa(1)) printf("-1\n"); else{ if(dis[n]==INF) printf("-2\n"); else printf("%d\n",dis[n]); } } return
0;} |
差分约束Poj 3169 Layout,布布扣,bubuko.com
原文地址：http://www.cnblogs.com/yigexigua/p/3770382.html
