Submission #1981811


Source Code Expand

#include<cstdio>
#include<vector>
#define pb push_back
const int MaxN=100010;
int N;
struct edge{int to;edge*next;}E[MaxN*2],*ne=E,*first[MaxN];
void link(int u,int v){*ne=(edge){v,first[u]};first[u]=ne++;}
int fa[MaxN],dep[MaxN],siz[MaxN],son[MaxN],top[MaxN];
void init(int i){
	siz[i]=1;
	for(edge*e=first[i];e;e=e->next)if(e->to!=fa[i]){
		fa[e->to]=i;
		dep[e->to]=dep[i]+1;
		init(e->to);
		if(siz[e->to]>siz[son[i]])son[i]=e->to;
		siz[i]+=siz[e->to];
	}
}
void hld(int i){
	for(edge*e=first[i];e;e=e->next)if(e->to!=fa[i])
		top[e->to]=e->to==son[i]?top[i]:e->to,hld(e->to);
}
int lca(int i,int j){
	while(top[i]!=top[j])dep[top[i]]>dep[top[j]]?i=fa[top[i]]:j=fa[top[j]];
	return dep[i]<dep[j]?i:j;
}
std::vector<int>us[MaxN],vs[MaxN],lcas[MaxN];
int pre[MaxN];
int find(int i){return pre[i]==i?i:pre[i]=find(pre[i]);}
bool solve(){
	for(int i=1;i<=N;i++)pre[i]=i;
	for(int d=1;d<N;d++)for(int i=0;i<us[d].size();i++){
		int u=us[d][i],v=vs[d][i],a=lcas[d][i],ec=0;
		for(;dep[u=find(u)]>dep[a];pre[u]=find(fa[u]))if(ec++)return 0;
		for(;dep[v=find(v)]>dep[a];pre[v]=find(fa[v]))if(ec++)return 0;
		if(!ec)return 0;
	}
	return 1;
}
int main(){
	scanf("%d",&N);
	for(int i=1,a,b;i<N;i++)scanf("%d%d",&a,&b),link(a,b),link(b,a);
	init(top[1]=1);
	hld(1);
	for(int i=1,a,b;i<N;i++){
		scanf("%d%d",&a,&b);
		int l=lca(a,b),d=dep[a]+dep[b]-dep[l]*2;
		us[d].pb(a);
		vs[d].pb(b);
		lcas[d].pb(l);
	}
	puts(solve()?"YES":"NO");
}

Submission Info

Submission Time
Task E - Blue and Red Tree
User mn3twe
Language C++14 (GCC 5.4.1)
Score 0
Code Size 1484 Byte
Status WA
Exec Time 76 ms
Memory 21248 KB

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:41:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&N);
                ^
./Main.cpp:42:65: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1,a,b;i<N;i++)scanf("%d%d",&a,&b),link(a,b),link(b,a);
                                                                 ^
./Main.cpp:46:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&a,&b);
                      ^

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 0 / 1400
Status
AC × 3
AC × 29
WA × 24
Set Name Test Cases
Sample sample1.txt, sample2.txt, sample3.txt
All sample1.txt, sample2.txt, sample3.txt, in1.txt, in10.txt, in11.txt, in12.txt, in13.txt, in14.txt, in15.txt, in16.txt, in17.txt, in18.txt, in19.txt, in2.txt, in20.txt, in21.txt, in22.txt, in23.txt, in24.txt, in25.txt, in26.txt, in27.txt, in28.txt, in29.txt, in3.txt, in30.txt, in31.txt, in32.txt, in33.txt, in34.txt, in35.txt, in36.txt, in37.txt, in38.txt, in39.txt, in4.txt, in40.txt, in41.txt, in42.txt, in43.txt, in44.txt, in45.txt, in46.txt, in47.txt, in5.txt, in6.txt, in7.txt, in8.txt, in9.txt, sample1.txt, sample2.txt, sample3.txt
Case Name Status Exec Time Memory
in1.txt AC 4 ms 10112 KB
in10.txt AC 58 ms 14976 KB
in11.txt WA 52 ms 15096 KB
in12.txt WA 53 ms 15096 KB
in13.txt WA 53 ms 14968 KB
in14.txt WA 53 ms 15096 KB
in15.txt WA 53 ms 14968 KB
in16.txt WA 52 ms 14968 KB
in17.txt WA 53 ms 14968 KB
in18.txt WA 53 ms 15096 KB
in19.txt WA 53 ms 14968 KB
in2.txt AC 4 ms 10112 KB
in20.txt WA 53 ms 14968 KB
in21.txt AC 54 ms 15096 KB
in22.txt AC 54 ms 15096 KB
in23.txt AC 54 ms 15096 KB
in24.txt AC 54 ms 15096 KB
in25.txt AC 54 ms 15224 KB
in26.txt AC 54 ms 15224 KB
in27.txt WA 54 ms 15096 KB
in28.txt WA 54 ms 15096 KB
in29.txt WA 54 ms 15096 KB
in3.txt AC 4 ms 10112 KB
in30.txt WA 54 ms 15096 KB
in31.txt WA 55 ms 15104 KB
in32.txt WA 55 ms 15104 KB
in33.txt WA 55 ms 15104 KB
in34.txt WA 55 ms 14976 KB
in35.txt WA 56 ms 15104 KB
in36.txt WA 56 ms 15104 KB
in37.txt WA 56 ms 15104 KB
in38.txt WA 73 ms 20352 KB
in39.txt WA 73 ms 21248 KB
in4.txt AC 58 ms 14976 KB
in40.txt WA 76 ms 20736 KB
in41.txt AC 56 ms 15232 KB
in42.txt AC 56 ms 15104 KB
in43.txt AC 56 ms 15232 KB
in44.txt AC 55 ms 15104 KB
in45.txt AC 56 ms 15104 KB
in46.txt AC 73 ms 21120 KB
in47.txt AC 74 ms 20608 KB
in5.txt AC 58 ms 15104 KB
in6.txt AC 72 ms 20352 KB
in7.txt AC 58 ms 15232 KB
in8.txt AC 58 ms 14976 KB
in9.txt AC 58 ms 14976 KB
sample1.txt AC 4 ms 10112 KB
sample2.txt AC 4 ms 10112 KB
sample3.txt AC 4 ms 10112 KB