提出 #26005569

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ソースコード 拡げる

#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define mp make_pair
#define x first
#define y second
#define WT int TT=read();while(TT--) 
#define NO puts("NO");
#define YES puts("YES");
using namespace std;

inline int read()
{
    char c=getchar();int x=0;bool f=0;
    for(;!isdigit(c);c=getchar())f^=!(c^45);
    for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
    if(f)x=-x;return x;
}

const int M=2e5+10;
int n,x,y,u[M],v[M],de1[M],de2[M],tag[M],fa[M],ans=1;
vector<int>e1[M],e2[M];

bool check(int u,int v)
{
	if (de2[u]==de2[v])
		return fa[u]!=fa[v];
	if (abs(de2[u]-de2[v])==1)
		return !(fa[u]==v||fa[v]==u);
	if (abs(de2[u]-de2[v])==2)
		return fa[fa[u]]!=v&&fa[fa[v]]!=u;
	return 1;
}

void dfs1(int u,int ff)
{
	de1[u]=de1[ff]+1;
	if (de1[u]>=de2[u])return;
	if (tag[u]){puts("-1");exit(0);}
	ans=max(ans,de2[u]);
	for (int i=0;i<e1[u].size();i++)
	{
		int to=e1[u][i];
		if (to==ff)continue;
		dfs1(to,u);
	}
}

void dfs2(int u,int ff)
{
	fa[u]=ff;de2[u]=de2[ff]+1;
	for (int i=0;i<e2[u].size();i++)
	{
		int to=e2[u][i];
		if (to==ff)continue;
		dfs2(to,u);
	}
}

signed main()
{
	n=read(),x=read(),y=read();
	for (int i=1;i<n;i++)
	{
		u[i]=read(),v[i]=read();
		e1[u[i]].pb(v[i]),e1[v[i]].pb(u[i]);
	}
	for (int i=1;i<n;i++)
	{
		int u=read(),v=read();
		e2[u].pb(v),e2[v].pb(u);
	}
	dfs2(y,0);
	for (int i=1;i<n;i++)
		if (check(u[i],v[i]))
			tag[u[i]]=tag[v[i]]=1;
	dfs1(x,0);cout<<(ans-1)*2<<endl;
	return 0;
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘void dfs1(long long int, long long int)’:
./Main.cpp:41:16: warning: comparison of integer expressions of different signedness: ‘long long int’ and ‘std::vector<long long int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   41 |  for (int i=0;i<e1[u].size();i++)
      |               ~^~~~~~~~~~~~~
./Main.cpp: In function ‘void dfs2(long long int, long long int)’:
./Main.cpp:52:16: warning: comparison of integer expressions of different signedness: ‘long long int’ and ‘std::vector<long long int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   52 |  for (int i=0;i<e2[u].size();i++)
      |               ~^~~~~~~~~~~~~

ジャッジ結果