Submission #1399492

---

Source Code Expand

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

#define fs first
#define sc second
#define pb emplace_back
#define mp make_pair
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)

using pii = pair<int, int>;
using vi = vector<int>;
using lint = long long;

const int inf = 1001001001;
const lint linf = 1001001001001001001ll;
const int mod = 1e9 + 7;
const int dx[]{0, 1, 0, -1, -1, -1, 1, 1}, dy[]{1, 0, -1, 0, -1, 1, -1, 1};

template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; } return a > b; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; } return a < b; }
template<typename T> inline void print(const T &x, string s = "\n") { cout << x << s; }
template<typename T> inline void print(const vector<T> &v, string s = " ") 
{ if (!v.size()) puts(""); rep(i, v.size()) cout << v[i] << (i + 1 == v.size() ? "\n" : s); }
inline bool inside(int y, int x, int H, int W) { return 0 <= y && y < H && 0 <= x && x < W; }
inline lint in() { lint x; std::cin>>x; return x; }

int n, x;
int h[110];
vector<int> g[110];
int ans = 0;

bool used[110];

int beet(int v) {
  if (used[v]) return 0;
  used[v] = true;
  int ret = h[v];
  rep(i, g[v].size()) {
    int u = beet(g[v][i]);
    if (u) ans += 2;
    ret += u;
  }

  return ret;
}

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

  rep(i, n - 1) {
    int a = in() - 1;
    int b = in() - 1;

    g[a].pb(b);
    g[b].pb(a);
  }

  beet(x - 1);
  cout << ans << endl;
}

Submission Info

Judge Result