delete pics to save space

history_source/信息学奥赛一本通/3.4.3.1.cpp

@@ -0,0 +1,54 @@
+#include<cstdio>
+#define maxn 100
+long long dis[maxn+1],oo=0x7fffffffffffffff;
+int num[maxn+1],tu[maxn+1][maxn+1],w[maxn+1][maxn+1],pre[maxn+1],queue[2*maxn+5],head,tail,n,e,a,b,c,s,t,i;
+bool exist[maxn+1];
+const int len=2*maxn+5;
+int main()
+{
+	freopen("msner.in","r",stdin);
+	freopen("msner.out","w",stdout);
+	scanf("%d%d",&n,&e);
+	for(i=1;i<=n;i++) dis[i]=oo;
+	for(i=0;i<e;i++)
+	{
+		scanf("%d%d%d",&a,&b,&c);
+		tu[a][num[a]++]=b;
+		tu[b][num[b]++]=a;
+		w[a][b]=w[b][a]=c;
+	}
+	s=1;
+	queue[tail++]=s;
+	exist[s]=1;
+	dis[s]=0;
+	while(head!=tail)
+	{
+		t=queue[head++];
+		head%=len;
+		exist[t]=0;
+		for(i=0;i<num[t];i++)
+			if(dis[tu[t][i]]>dis[t]+w[t][tu[t][i]])
+			{
+				dis[tu[t][i]]=dis[t]+w[t][tu[t][i]];
+				pre[tu[t][i]]=t;
+				if(!exist[tu[t][i]])
+				{
+					queue[tail++]=tu[t][i];
+					tail%=len;
+					exist[tu[t][i]]=1;
+				}
+			}
+	}
+	long long max=0;
+	for(i=1;i<=n;i++)
+	{
+		if(dis[i]==oo)
+		{
+			printf("-1\n");
+			return 0;
+		}
+		if(dis[i]>max) max=dis[i];
+	}
+	printf("%d\n",max);
+	return 0;
+}