제출 #647428

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
647428		Pety	Stranded Far From Home (BOI22_island)	C++14	100 / 100	351 ms	47300 KiB

island

#include <bits/stdc++.h>
#define ll long long

using namespace std;

const int INF = 1e9;
const int MOD = 1e9 + 7;

int n, m, val[200002], ind[200002], p[200002], ok[200002];
ll sz[200002];
vector<int>G2[200002];
vector<int>G[200002];


int find (int x) {
  if (p[x] == x)
    return x;
  return p[x] = find(p[x]); 
}

void Union (int a, int b) {
  a = find(a);
  b = find(b);
  if (a != b) {
    G[a].push_back(b);
    G[b].push_back(a);
    p[b] = a;
  }
}

bool cmp (int a, int b) {
  if (val[a] == val[b])
     return a < b;
  return val[a] < val[b];
}

void dfs (int nod, int par) {
  assert(par == 0 || val[nod] <= val[par]);

  sz[nod] = val[nod];
  for (auto it : G[nod]) {
    if (it == par)
      continue;
    dfs(it, nod);
    sz[nod] += sz[it];
  }
  ok[nod] = (sz[nod] >= val[par]);
}

void dfs2 (int nod, int par, bool idk) {
  for (auto it : G[nod]) {
    if (it == par)
      continue;
    dfs2(it, nod, (idk & ok[it]));
  }
  ok[nod] = idk;
}

int main () 
{
  ios_base::sync_with_stdio(false);
  cin.tie(0); cout.tie(0);
  cin >> n >> m;
  for (int i = 1; i <= n; i++) 
    cin >> val[i];
  for (int i = 1; i <= m; i++) {  
    int x, y;
    cin >> x >> y;
    G2[x].push_back(y);
    G2[y].push_back(x);
  }
  for (int i = 1; i <= n; i++)
    ind[i] = p[i] = i;
  sort(ind + 1, ind + n + 1, cmp);  
  for (int i = 1; i <= n; i++)
    for (auto it : G2[ind[i]])
      if (make_pair(val[it], it) <= make_pair(val[ind[i]], ind[i]))
        Union(ind[i], it);
  dfs(find(1), 0);
  dfs2(find(1), 0, 1);
  for (int i = 1; i <= n; i++)
    cout << ok[i];
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 30 / 30
• Subtask 5: 35 / 35