delete pics to save space

history_source/挑战程序设计竞赛/2.5.6.1.cpp

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+#include<cstdio>
+#include<vector>
+#include<queue>
+#include<algorithm>
+#include<utility>
+using namespace std;
+struct edge
+{
+	int to,cost;
+	edge(){}
+	edge(int t,int c)
+	{
+		to=t;
+		cost=c;
+	}
+};
+#define P pair<int,int>
+int n,r;
+vector<edge> G[5001];
+int dist[5001],dist2[5001];
+const int oo=1<<30;
+void solve()
+{
+	priority_queue<P,vector<P>,greater<P> > que;
+	fill(dist,dist+n,oo);
+	fill(dist2,dist2+n,oo);
+	dist[0]=0;
+	que.push(P(0,0));
+	while(!que.empty())
+	{
+		P p=que.top();que.pop();
+		int v=p.second,d=p.first;
+		if(dist2[v]<d) continue;
+		for(int i=0;i<G[v].size();i++)
+		{
+			edge e=G[v][i];
+			int d2=d+e.cost;
+			if(dist[e.to]>d2)
+			{
+				swap(dist[e.to],d2);
+				que.push(make_pair(dist[e.to],e.to));
+			}
+			if(dist2[e.to]>d2&&dist[e.to]<d2)
+			{
+				dist2[e.to]=d2;
+				que.push(P(dist2[e.to],e.to));
+			}
+		}
+	}
+	printf("%d\n",dist2[n-1]);
+}
+void init()
+{
+	int f,t,c;
+	scanf("%d%d",&n,&r);
+	for(int i=0;i<r;i++)
+	{
+		scanf("%d%d%d",&f,&t,&c);
+		G[f].push_back(edge(t,c));
+	}
+}
+int main()
+{
+	init();
+	solve();
+	return 0;
+}