delete pics to save space

1.3385.cpp

@@ -0,0 +1,58 @@
+#include<cstdio>
+#include<cstring>
+#include<queue>
+#include<algorithm>
+using namespace std;
+const int maxn=2005;
+const int maxm=6005;
+struct Edge { int v,w; Edge *next; };
+Edge *G[maxn],mem[maxm],*ecnt;
+inline void AddEdge(int u,int v,int w) { ecnt->v=v; ecnt->w=w; ecnt->next=G[u]; G[u]=ecnt++; }
+int T,n,m;
+int dis[maxn],len[maxn];
+bool inq[maxn],searched[maxn];
+bool spfa(int s)
+{
+	queue<int> que;
+	memset(inq,false,sizeof(inq));
+	memset(dis,0x3F,sizeof(dis));
+	que.push(s);
+	dis[s]=0; inq[s]=true; len[s]=0; searched[s]=true;
+	while(que.size())
+	{
+		int u=que.front(); que.pop(); inq[u]=false;
+		for(Edge *it=G[u];it;it=it->next)
+			if(dis[it->v]>dis[u]+it->w)
+			{
+				dis[it->v]=dis[u]+it->w;
+				len[it->v]=len[u]+1;
+				searched[it->v]=true;
+				if(len[it->v]>=n) return true;
+				if(!inq[it->v]) { inq[it->v]=true; que.push(it->v); }
+			}
+	}
+	return false;
+}
+bool check()
+{
+	memset(searched,0,sizeof(searched));
+	for(int i=1;i<=n;i++) if(!searched[i]&&spfa(i)) return true;
+	return false;
+}
+int main()
+{
+	scanf("%d",&T);
+	while(T-->0)
+	{
+		memset(G,0,sizeof(G)); ecnt=mem;
+		scanf("%d%d",&n,&m);
+		for(int i=0;i<m;i++)
+		{
+			int a,b,w; scanf("%d%d%d",&a,&b,&w);
+			AddEdge(a,b,w);
+			if(w>=0) AddEdge(b,a,w);
+		}
+		puts(check()?"YE5":"N0");
+	}
+	return 0;
+}