Be careful not to use Dijkstra!
Be careful not to use Dijkstra! !
Be careful not to use Dijkstra! ! !
Because there are negative side right
#include<cstdio>
#include<queue>
#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;
int n,m,value[100005],head[500005],dis[500005],vis[500005],cnt;
struct edge{
int v,w,next;
}e[5000005];
inline void add(int u,int v,int w){
e[++cnt].v=v;
e[cnt].w=w;
e[cnt].next=head[u];
head[u]=cnt;
}
inline void emm(int x,int y){
add(x,y,0);add(x+n,y+n,0);add(x+2*n,y+2*n,0);
add(x,y+n,-value[x]);
add(x+n,y+2*n,value[x]);
}
inline void spfa(){
memset(dis,-0x3f,sizeof(dis));
queue<int> q;
q.push(1);
dis[1]=0;
while(!q.empty()){
int u=q.front();
q.pop();
vis[u]=0;
for(int i=head[u];i!=-1;i=e[i].next){
int v=e[i].v;
if(dis[v]<dis[u]+e[i].w){
dis[v]=dis[u]+e[i].w;
if(!vis[v]){
vis[v]=1;
q.push(v);
}
}
}
}
}
/*
inline void dijkstra(){
memset(vis,0,sizeof(vis));
memset(dis,-0x3f,sizeof(dis));
priority_queue<node> q;
dis[1]=0;
q.push((node){0,1});
while(!q.empty()){
int x=q.top().u;
q.pop();
if(vis[x])continue;
vis[x]=1;
for(int i=head[x];i!=-1;i=e[i].next){
int y=e[i].v;
if(dis[y]<dis[x]+e[i].w){
dis[y]=dis[x]+e[i].w;
q.push((node){dis[y],y});
}
}
}
}
*/
int main(){
memset(head,-1,sizeof(head));
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++)scanf("%d",&value[i]);
for(int i=1;i<=m;i++){
int x,y,z;
scanf("%d%d%d",&x,&y,&z);
emm(x,y);
if(z==2){
emm(y,x);
}
}
add(n,0,0);add(3*n,0,0);
spfa();
printf("%d\n",dis[0]);
}