Submission #4044642

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repi(i,a,b) for(int i=int(a);i<(int)(b);i++)
#define reps(i,n) for(int i=0;i<=(int)(n);i++)
#define all(x) (x).begin(),(x).end()
#define foreach(u,v) for(auto (u) : (v))
#define pb push_back
#define mp make_pair
#define mt make_tuple

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;

const int inf = 1e9;
const ll linf = 1e18;
const ll mod = 1e9 + 7;
const double eps = 1e-9;

int n;
vi h(100);
vi es[100];

pii dfs(int x, int y)
{
  pii ret = mp(h[x], 2);
  foreach(e, es[x]){
    if(e == y) continue;
    pii p = dfs(e, x);
    if(p.first != 0){
      ret.first += p.first;
      ret.second += p.second;
    }
  }
  return ret;
}

int main()
{
  int x;
  cin >> n >> x;
  rep(i, n) cin >> h[i];

  rep(i, n-1){
    int a, b;
    cin >> a >> b;
    a--; b--;
    es[a].pb(b);
    es[b].pb(a);
  }

  pii ans = dfs(x-1, -1);
  cout << ans.second-2 << endl;

  return 0;
}

Submission Info

Judge Result