本题可以直接套用最小生成树模板,但是要稍作变通,即循环终止条件应该由边数等于顶点数-1(边数==n-1
)变为顶点1和顶点n都已加入到树中(Find(1)==Find(n)
)
代码如下
#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
struct EDGE{
int u,v,w;
}edge[200001];
int cmp(EDGE a, EDGE b){
return a.w< b.w;
}
int Arry[100001];
int Find(int num){
int root = num,tmp;
while(root != Arry[root]){
root = Arry[root];
}
while(root != num){
tmp = Arry[num];
Arry[num] = root;
num = tmp;
}
return num;
}
bool Union(int a,int b){
int ar = Find(a);
int br = Find(b);
if(ar != br){
Arry[ar] = br;
return true;
}
return false;
}
int main()
{
int n,m,a,b,c,ans = 0, num = 0;
scanf("%d%d", &n, &m);
for(int i = 0; i < m; i++){
scanf("%d%d%d", &edge[i].u, &edge[i].v,&edge[i].w);
}
for(int i = 0; i < n; i++) Arry[i] = i;
sort(edge, edge+m, cmp);
for(int i = 0; i < m; i++){
if(Union(edge[i].u,edge[i].v)){
ans = edge[i].w;
if(Find(1)==Find(n)) break;
}
}
printf("%d\n", ans);
return 0;
}