Submission #1645777


Source Code Expand

#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<ctime>
#include<queue>
#include<set>
#include<map>
#include<stack>
#include<bitset>
using namespace std;
typedef long long LL;
const int N=2e5;
int gi() {
	int w=0;bool q=1;char c=getchar();
	while ((c<'0'||c>'9') && c!='-') c=getchar();
	if (c=='-') q=0,c=getchar();
	while (c>='0'&&c <= '9') w=w*10+c-'0',c=getchar();
	return q? w:-w;
}
int a[N];
int head[N],nxt[N],to[N];
inline LL dfs(int k,int fa) {
	if (!nxt[head[k]])
		return a[k];
	LL s=a[k]<<1;
	for (int i=head[k];i;i=nxt[i])
		if (to[i]!=fa)
			s-=dfs(to[i],k);
	if (s<0) puts("NO"),exit(0);
	return s;
}
inline bool check(int n) {
	int i;
	for (i=1;i<=n;i++)
		if (nxt[head[i]])
			return !dfs(i,0);
	return a[1]==a[2];
}
int main()
{
	int n=gi(),i,a,b,tot=0;
	for (i=1;i<=n;i++) ::a[i]=gi();
	for (i=1;i<n;i++) {
		a=gi(),b=gi();
		to[++tot]=b,nxt[tot]=head[a],head[a]=tot;
		to[++tot]=a,nxt[tot]=head[b],head[b]=tot;
	}
	puts(check(n)?"YES":"NO");
	return 0;
}

Submission Info

Submission Time
Task C - Cleaning
User laofu
Language C++14 (GCC 5.4.1)
Score 0
Code Size 1114 Byte
Status WA
Exec Time 23 ms
Memory 4480 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 0 / 700
Status
AC × 3
AC × 42
WA × 9
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, 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 20 ms 2560 KB
in10.txt AC 21 ms 2560 KB
in11.txt AC 22 ms 4096 KB
in12.txt AC 23 ms 4096 KB
in13.txt AC 17 ms 4480 KB
in14.txt AC 17 ms 4224 KB
in15.txt AC 1 ms 256 KB
in16.txt AC 1 ms 256 KB
in17.txt AC 1 ms 256 KB
in18.txt AC 1 ms 256 KB
in19.txt WA 20 ms 2560 KB
in2.txt AC 20 ms 2560 KB
in20.txt WA 21 ms 2560 KB
in21.txt WA 21 ms 2560 KB
in22.txt WA 20 ms 2560 KB
in23.txt WA 20 ms 2560 KB
in24.txt AC 20 ms 2560 KB
in25.txt AC 1 ms 256 KB
in26.txt AC 20 ms 2560 KB
in27.txt AC 20 ms 2560 KB
in28.txt AC 1 ms 256 KB
in29.txt AC 14 ms 2560 KB
in3.txt AC 20 ms 2560 KB
in30.txt WA 1 ms 256 KB
in31.txt WA 20 ms 2560 KB
in32.txt WA 20 ms 2560 KB
in33.txt AC 20 ms 2560 KB
in34.txt AC 20 ms 2688 KB
in35.txt AC 20 ms 2560 KB
in36.txt AC 20 ms 2560 KB
in37.txt AC 1 ms 256 KB
in38.txt AC 18 ms 2560 KB
in39.txt AC 17 ms 2560 KB
in4.txt AC 20 ms 2560 KB
in40.txt AC 19 ms 2560 KB
in41.txt AC 19 ms 2560 KB
in42.txt AC 20 ms 2560 KB
in43.txt AC 20 ms 2560 KB
in44.txt WA 20 ms 2560 KB
in45.txt AC 20 ms 2560 KB
in5.txt AC 20 ms 2560 KB
in6.txt AC 20 ms 2560 KB
in7.txt AC 18 ms 2304 KB
in8.txt AC 6 ms 768 KB
in9.txt AC 20 ms 2560 KB
sample1.txt AC 1 ms 256 KB
sample2.txt AC 1 ms 256 KB
sample3.txt AC 1 ms 256 KB