RT

信息长这样

Judger Internal Error

Traceback (most recent call last):
  File "/app/luogu-judger/source/tasks/Compile.py", line 60, in compile
    enable_o2=enable_o2)
  File "/app/luogu-judger/source/compiler/Compiler.py", line 69, in compile
    writable_files=[work_dest_path, work_dir])
  File "/app/luogu-judger/source/executor/LrunExecutor.py", line 43, in execute
    cwd=work_dir, stdout=subprocess.DEVNULL)
  File "/usr/lib/python3.7/subprocess.py", line 323, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/usr/lib/python3.7/subprocess.py", line 775, in __init__
    restore_signals, start_new_session)
  File "/usr/lib/python3.7/subprocess.py", line 1453, in _execute_child
    restore_signals, start_new_session, preexec_fn)
BlockingIOError: [Errno 11] Resource temporarily unavailable

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
inline int read(){
	register int x=0,f=0,ch=getchar();
	while('0'>ch||ch>'9')f^=ch=='-',ch=getchar();
	while('0'<=ch&&ch<='9')x=(x<<1)+(x<<3)+(ch^'0'),ch=getchar();
	return f?-x:x;
}
const int MAX=3e5+5;
int n,m; 
struct A{int s,t,w;}a[MAX];
struct E{int e,next,w;}e[MAX<<1];int cnt=1,head[MAX],tot;
struct EDG{int u,v,w;}edg[MAX];
inline void add(int u,int v,int w){e[cnt]=(E){v,head[u],w};head[u]=cnt++;}
int l=0,r,mid,k;
int fa[MAX][26],P[MAX],D[MAX],dep[MAX];
void dfs(int x,int f,int w){
	fa[x][0]=f,dep[x]=dep[f]+1;D[x]=D[f]+w;
	for(register int i=1;(1<<i)<=dep[x];++i)fa[x][i]=fa[fa[x][i-1]][i-1];
	for(register int i=head[x];i;i=e[i].next)if(e[i].e!=f)dfs(e[i].e,x,e[i].w);
}
inline int lca(int x,int y){
	if(dep[x]>dep[y])swap(x,y);
	for(register int i=25;i>=0;--i)if(dep[x]+(1<<i)<=dep[y])y=fa[y][i];
	if(x==y)return x;
	for(register int i=25;i>=0;--i)if(fa[x][i]!=fa[y][i])x=fa[x][i],y=fa[y][i];
	return fa[x][0];
}
void dfs2(int x,int f){
	P[x]=D[x];
	for(register int i=head[x];i;i=e[i].next){
		if(e[i].e!=f){
			dfs2(e[i].e,x);
			P[x]+=P[e[i].e];
		}
	}
}
inline int dist(int x,int y){return D[x]+D[y]-2*D[lca(x,y)];}
inline void work(int x,int y){++D[x],++D[y],D[lca(x,y)]-=2;}
inline bool cmp(A x,A y){return x.w>y.w;}
inline bool check(int t){
	memset(D,0,sizeof(D));tot=0;k=0;
	for(register int i=1;i<=m;++i)if(a[i].w>t)++tot,work(a[i].s,a[i].t);
	dfs2(1,0);
	for(register int i=1;i<n;++i)if(D[edg[i].u]==tot&&edg[i].w>k)k=e[i].w;
	for(register int i=1;i<=m;++i)if(a[i].w-k>t)return false;
	return true;
} 
signed main(){
	n=read(),m=read();
	for(register int i=1,u,v,w;i<n;++i)u=read(),v=read(),w=read(),add(u,v,w),add(v,u,w),edg[i]=(EDG){u,v,w},r+=w;
	dfs(1,0,0);
	for(register int i=1;i<n;++i)if(dep[edg[i].u]<dep[edg[i].v])swap(edg[i].u,edg[i].v);
	for(register int i=1,s,t;i<=m;++i)s=read(),t=read(),a[i]=(A){s,t,dist(s,t)};
	sort(a+1,a+1+m,cmp);
	while(l<r){
		mid=l+r>>1;
		if(check(mid))r=mid;
		else l=mid+1;
	}
	printf("%d\n",l);
	return 0;
}