Submission #1372882


Source Code Expand

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <cassert>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>

using namespace std;

#define f first
#define s second
#define pb push_back
#define pp pop_back
#define mp make_pair
#define ll long long
#define ld double
#define ull unsigned long long
#define PI pair < int, int > 

const int N = 5e5 + 123;
const int M = 123;
const ld Pi = acos(-1);
const ll Inf = 1e18;
const int inf = 1e9;
const int mod = 1e9 + 7;
const int Sz = 501;
const int MOD = 1e9 + 7;

void add(int &a, int b) {
  a += b;
  if (a >= mod) a -= mod;
}
int mult(int a, int b) {
  return 1ll * a * b % mod;
}
int sum(int a, int b) {
  add(a, b);
  return a;
}

int n, a[N];
vector < int > g[N];

ll dfs(int v, int p = -1) {
  vector < ll > now;
  ll x = a[v];
  ll y = 0;
  for (auto to : g[v]) {
    if (to != p) {
      ll tmp = dfs(to, v);
      y += tmp;
      now.pb(tmp);
    }
  }
  if (now.size() == 0) return x;
  if (x > y) {
    cout << "NO\n";
    exit(0);
  }
  ll z = y - x;
  sort(now.begin(), now.end());
  for (int i = 0;i + 1 < now.size();i++) {
    if (z == 0) break;
    ll cur = min(now[i], z);
    x -= cur;
    y -= cur;
    z -= cur;
    now[i] -= cur;
    now[i + 1] -= cur;
  }
  if (z > 0) {
    cout << "NO\n";
    exit(0);
  }
  return x;
}
void solve() { 
  cin >> n;
  for (int i = 1;i <= n;i++) cin >> a[i];
  for (int i = 1, u, v;i < n;i++) {
    cin >> u >> v;
    g[u].pb(v);
    g[v].pb(u);
  }
  if (n == 2) {
    if (a[1] != a[2]) cout << "NO\n";
    else cout << "YES\n";
    return;
  }
  int rt = 1;
  while(g[rt].size() == 1) rt++;
  assert(rt <= n && g[rt].size() > 1);
  //cout << "rt = " << rt << " " << dfs(rt) << endl;
  if (dfs(rt) == 0) cout << "YES\n";
  else cout << "NO\n";
}

int main() {
  #ifdef wws
   freopen("in", "r", stdin);
   // freopen("in", "w", stdout);
  #endif 
  ios_base::sync_with_stdio(0);
  int tt = 1; 
  while(tt--) solve();
  return 0;
}

Submission Info

Submission Time
Task C - Cleaning
User SmallBoy
Language C++14 (GCC 5.4.1)
Score 0
Code Size 2411 Byte
Status WA
Exec Time 62 ms
Memory 24960 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 0 / 700
Status
AC × 1
WA × 2
AC × 34
WA × 17
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 WA 51 ms 15744 KB
in10.txt WA 52 ms 15744 KB
in11.txt AC 57 ms 23296 KB
in12.txt AC 57 ms 23296 KB
in13.txt AC 53 ms 24960 KB
in14.txt AC 53 ms 23680 KB
in15.txt WA 5 ms 12544 KB
in16.txt AC 5 ms 12544 KB
in17.txt AC 5 ms 12544 KB
in18.txt AC 5 ms 12544 KB
in19.txt AC 47 ms 15744 KB
in2.txt WA 53 ms 15744 KB
in20.txt AC 46 ms 15744 KB
in21.txt AC 44 ms 15744 KB
in22.txt AC 52 ms 15744 KB
in23.txt AC 50 ms 15744 KB
in24.txt AC 48 ms 15744 KB
in25.txt AC 5 ms 12544 KB
in26.txt AC 46 ms 15744 KB
in27.txt AC 45 ms 15744 KB
in28.txt AC 5 ms 12544 KB
in29.txt AC 41 ms 15744 KB
in3.txt WA 52 ms 15744 KB
in30.txt AC 5 ms 12544 KB
in31.txt AC 52 ms 15744 KB
in32.txt AC 46 ms 15744 KB
in33.txt WA 62 ms 15744 KB
in34.txt WA 52 ms 15744 KB
in35.txt AC 51 ms 15744 KB
in36.txt AC 52 ms 15744 KB
in37.txt AC 5 ms 12544 KB
in38.txt AC 51 ms 15744 KB
in39.txt AC 52 ms 15744 KB
in4.txt WA 54 ms 15744 KB
in40.txt AC 49 ms 15744 KB
in41.txt AC 49 ms 15744 KB
in42.txt AC 50 ms 15744 KB
in43.txt AC 50 ms 15744 KB
in44.txt AC 52 ms 15744 KB
in45.txt AC 52 ms 15744 KB
in5.txt WA 52 ms 15744 KB
in6.txt WA 54 ms 15744 KB
in7.txt WA 49 ms 15488 KB
in8.txt WA 15 ms 13312 KB
in9.txt WA 52 ms 15744 KB
sample1.txt WA 5 ms 12544 KB
sample2.txt AC 5 ms 12544 KB
sample3.txt WA 5 ms 12544 KB