用到了 Bellman-Ford Shortist Path Algorithm
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| #include<iostream>
using namespace std;
#define INF 1e9
struct edge{
int from,to,cost;
};
int d[505],c[505],n,m;
edge a[10050];
void shortistPath(){
while(1){
bool update=false;
for(int i=0;i<2*m;i++){
if(d[a[i].from]!=INF &&
d[a[i].to]>d[a[i].from]+a[i].cost+c[a[i].to]){
d[a[i].to]=d[a[i].from]+a[i].cost+c[a[i].to];
update=true;
}
}
if(!update) break;
}
}
int main(){
ios::sync_with_stdio(false);cin.tie(0);
cin>>n;
for(int i=1;i<=n;i++){
cin>>c[i];
d[i]=INF;
}
cin>>m;
for(int i=0;i<m;i++){
cin>>a[i].from>>a[i].to>>a[i].cost;
a[m+i].from=a[i].to;
a[m+i].to=a[i].from;
a[m+i].cost=a[i].cost;
}
d[1]=0;
shortistPath();
if(d[n]!=INF){
cout<<d[n];
}else{
cout<<"-1";
}
return 0;
}
|