Submission #286823

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Source Code Expand

#include <iostream>
#include <cstdio>
#include <vector>
#include <list>
#include <cmath>
#include <fstream>
#include <algorithm>
#include <string>
#include <queue>
#include <set>
#include <map>
#include <complex>
#include <iterator>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <stack>
#include <climits>
#include <deque>
#include <bitset>
#include <cassert>
#include <ctime>
using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
// adjust problem by problem
const double EPS=1e-8;
const double PI=acos(-1.0);
// rep macro
#define REP(i,x,n) for(int i=x;i<(int)(n);++i)
#define rep(i,n) REP(i,0,n)
#define RREP(i,x,n) for(int i=x;i>=(int)(n);--i)
#define rrep(i,n) RREP(i,n,0)
#ifdef __GNUC__
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
int popcount(int n){return __builtin_popcount(n);}
int popcount(ll n){return __builtin_popcountll(n);}
#endif
#ifndef __GNUC__
int popcount(unsigned int n){int cnt=0;for(int i=0;i<32;i++)if((n>>i)&1)cnt++;return cnt;}
int popcountll(unsigned ll n){int cnt=0;for(int i=0;i<64;i++)if((n>>i)&1)cnt++;return cnt;}
#endif
template<class T>int SIZE(T a){return a.size();}
template<class T>string IntToString(T num){string res;stringstream ss;ss<<num;return ss.str();}
template<class T>T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template<class T>T lcm(T a,T b){return a/gcd(a,b)*b;}
ll getTen(int a){return (a<=0)?1:(getTen(a-1)*10);}
bool EQ(double a,double b){return abs(a-b)<EPS;}
void fastStream(){cin.tie(0);std::ios_base::sync_with_stdio(0);}
vector<string> split(string str,char del){
  vector<string> res;
  for(int i=0,s=0;i<SIZE(str);i++){
    if(str[i]==del){if(i-s!=0)res.push_back(str.substr(s,i-s));s=i+1;}
    else if(i==SIZE(str)-1){res.push_back(str.substr(s));}
  }
  return res;
}
struct TimeWatch{
  clock_t start_,end_;
  void start(){start_=clock();}
  double stop(){return (double)(clock()-start_)/CLOCKS_PER_SEC;}
};

int N,X;
int H[101];
int A[101];
int B[101];

int sums[101];
vector<int>G[101];

int dfs(int pos,int par){
  int cnt = H[pos];
  for(int to : G[pos]){
    if(to == par)continue;
    cnt += dfs(to, pos);
  }
  //cout<<pos<<" "<<cnt<<endl;
  sums[pos] = cnt;
  return cnt;
}

int dfs2(int pos,int par){
  int res=0;
  for(int to : G[pos]){
    if(to == par)continue;
    if(sums[to]>0){
      res+=(dfs2(to, pos)+1);
    }
  }
  return res+1;
}

int main(){

  cin>>N>>X;
  X--;
  for(int i=0;i<N;i++)cin>>H[i];
  for(int i=0;i<N-1;i++){
    cin>>A[i]>>B[i];
    A[i]--;B[i]--;
    G[A[i]].push_back(B[i]);
    G[B[i]].push_back(A[i]);
  }
  dfs(X, -1);
  cout<<dfs2(X, -1)-1<<endl;
  
  return 0;
}

Submission Info

Judge Result