Submission #1511618
Source Code Expand
//by yjz #include<bits/stdc++.h> using namespace std; #define FF first #define SS second #define PB push_back #define MP make_pair #define bged(v) (v).begin(),(v).end() #define foreach(it,s) for(__typeof((s).begin()) it=(s).begin();it!=(s).end();it++) typedef long long ll; const int Imx=2147483647; const ll Lbig=2e18; const int mod=1e9+7; //My i/o stream struct fastio { char s[100000]; int it,len; fastio(){it=len=0;} inline char get() { if(it<len)return s[it++];it=0; len=fread(s,1,100000,stdin); if(len==0)return EOF;else return s[it++]; } bool notend() { char c=get(); while(c==' '||c=='\n')c=get(); if(it>0)it--; return c!=EOF; } }_buff; #define geti(x) x=getnum() #define getii(x,y) geti(x),geti(y) #define getiii(x,y,z) getii(x,y),geti(z) #define puti(x) putnum(x),putchar(' ') #define putii(x,y) puti(x),puti(y) #define putiii(x,y,z) putii(x,y),puti(z) #define putsi(x) putnum(x),putchar('\n') #define putsii(x,y) puti(x),putsi(y) #define putsiii(x,y,z) putii(x,y),putsi(z) inline ll getnum() { ll r=0;bool ng=0;char c;c=_buff.get(); while(c!='-'&&(c<'0'||c>'9'))c=_buff.get(); if(c=='-')ng=1,c=_buff.get(); while(c>='0'&&c<='9')r=r*10+c-'0',c=_buff.get(); return ng?-r:r; } template<class T> inline void putnum(T x) { if(x<0)putchar('-'),x=-x; register short a[20]={},sz=0; while(x)a[sz++]=x%10,x/=10; if(sz==0)putchar('0'); for(int i=sz-1;i>=0;i--)putchar('0'+a[i]); } inline char getreal(){char c=_buff.get();while(c==' '||c=='\n')c=_buff.get();return c;} int n,a[100111]; ll tot,dp[100111]; vector<int> con[100111]; void dfs(int x,int pre=-1) { // cerr<<"dfs:"<<x<<endl; if(con[x].size()==1) { dp[x]=a[x]; return; } ll st=0; for(int i=0;i<con[x].size();i++) { if(con[x][i]==pre)continue; dfs(con[x][i],x); dp[x]+=dp[con[x][i]]; } for(int i=0;i<con[x].size();i++) { if(con[x][i]==pre)continue; st=max(st,2*dp[con[x][i]]-dp[x]); } if(a[x]>dp[x]) { puts("NO"); exit(0); } ll comb=dp[x]-a[x]; if(2*comb>dp[x]-st) { puts("NO"); exit(0); } dp[x]-=2*comb; // cerr<<x<<":"<<dp[x]<<endl; } int main() { geti(n); for(int i=1;i<=n;i++)geti(a[i]); if(n==1) { puts("YES"); return 0; } if(n==2) { if(a[1]==a[2])puts("YES"); else puts("NO"); return 0; } for(int i=1;i<n;i++) { int x,y; getii(x,y); con[x].PB(y); con[y].PB(x); } for(int i=1;i<=n;i++) { if(con[i].size()==1) { tot+=a[i]; } } if(tot&1) { puts("NO"); return 0; } tot/=2; int rt=1; while(con[rt].size()==1)rt++; dfs(rt); if(dp[rt]==0)puts("YES"); else puts("NO"); return 0; }
Submission Info
Submission Time | |
---|---|
Task | C - Cleaning |
User | fizzydavid |
Language | C++14 (GCC 5.4.1) |
Score | 700 |
Code Size | 2704 Byte |
Status | AC |
Exec Time | 25 ms |
Memory | 13696 KB |
Judge Result
Set Name | Sample | All | ||||
---|---|---|---|---|---|---|
Score / Max Score | 0 / 0 | 700 / 700 | ||||
Status |
|
|
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 | 25 ms | 7040 KB |
in10.txt | AC | 24 ms | 7040 KB |
in11.txt | AC | 25 ms | 12416 KB |
in12.txt | AC | 25 ms | 12416 KB |
in13.txt | AC | 23 ms | 13696 KB |
in14.txt | AC | 23 ms | 12800 KB |
in15.txt | AC | 2 ms | 2560 KB |
in16.txt | AC | 2 ms | 2560 KB |
in17.txt | AC | 2 ms | 2560 KB |
in18.txt | AC | 2 ms | 2560 KB |
in19.txt | AC | 22 ms | 7040 KB |
in2.txt | AC | 24 ms | 7040 KB |
in20.txt | AC | 20 ms | 6272 KB |
in21.txt | AC | 20 ms | 6272 KB |
in22.txt | AC | 24 ms | 7040 KB |
in23.txt | AC | 23 ms | 7040 KB |
in24.txt | AC | 22 ms | 7040 KB |
in25.txt | AC | 2 ms | 2560 KB |
in26.txt | AC | 20 ms | 6272 KB |
in27.txt | AC | 21 ms | 6272 KB |
in28.txt | AC | 2 ms | 2560 KB |
in29.txt | AC | 19 ms | 6272 KB |
in3.txt | AC | 24 ms | 7040 KB |
in30.txt | AC | 2 ms | 2560 KB |
in31.txt | AC | 23 ms | 7040 KB |
in32.txt | AC | 21 ms | 7040 KB |
in33.txt | AC | 24 ms | 7040 KB |
in34.txt | AC | 24 ms | 7040 KB |
in35.txt | AC | 24 ms | 7040 KB |
in36.txt | AC | 24 ms | 7040 KB |
in37.txt | AC | 2 ms | 2688 KB |
in38.txt | AC | 23 ms | 7040 KB |
in39.txt | AC | 23 ms | 7040 KB |
in4.txt | AC | 25 ms | 7040 KB |
in40.txt | AC | 21 ms | 7040 KB |
in41.txt | AC | 21 ms | 7040 KB |
in42.txt | AC | 19 ms | 6272 KB |
in43.txt | AC | 22 ms | 7040 KB |
in44.txt | AC | 25 ms | 7040 KB |
in45.txt | AC | 19 ms | 6272 KB |
in5.txt | AC | 24 ms | 7040 KB |
in6.txt | AC | 24 ms | 7040 KB |
in7.txt | AC | 22 ms | 6656 KB |
in8.txt | AC | 7 ms | 3712 KB |
in9.txt | AC | 24 ms | 7040 KB |
sample1.txt | AC | 2 ms | 2560 KB |
sample2.txt | AC | 2 ms | 2560 KB |
sample3.txt | AC | 2 ms | 2560 KB |