从c++14换成c++20快了1.12s!!!```cpp #include<bits/stdc++.h> using namespace std; struct edge { int u; int v; int w; }; struct edge e[10000000]; int n,m; int f[10000010]={0},count1=0; long long sum=0; int getf(int v) { if(f[v]==v) return v; else { f[v]=getf(f[v]); return f[v]; } } int merge(int v,int u) { int t1,t2; t1=getf(v); t2=getf(u); if(t1!=t2) { f[t2]=t1; return 1; } return 0; } void quicksort(int left,int right) { int i,j; struct edge t;

if(left>right)
	return;
i=left;
j=right;
while(i!=j) {
	while(e[j].w>=e[left].w && i<j)
		j--;
	while(e[i].w<=e[left].w && i<j)
		i++;
	if(i<j) {
		t=e[i];
		e[i]=e[j];
		e[j]=t;
	}
}
t=e[left];
e[left]=e[i];
e[i]=t;
quicksort(left,i-1);
quicksort(i+1,right);
return;

} int main() { int n,m,s,t; scanf("%d%d%d%d",&n,&m,&s,&t); for(int i=1;i<=m;i++) scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w); quicksort(1,m); int left=1,right=10000,mid; while(left<right) { mid=(left+right)/2; int left1=1,right1=m,mid1; while(left1<right1) { mid1=(left+right)/2; if(e[mid1].w>mid) right1=mid1-1; else left1=mid1+1; } for(int i=1;i<=mid1;i++) { if(merge(e[i].u,e[i].v)) { count1++; sum+=e[i].w; } if(count1==n-1) break; } if(count1!=n-1) left=mid+1; else right=mid-1; } return 0; }