Submission #614230

#	Time	Username	Problem	Language	Result	Execution time	Memory
614230		Plurm	Stranded Far From Home (BOI22_island)	C++11	0 / 100	129 ms	15660 KiB

island

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

int s[200005];
vector<int> g[200005];
int n, m;
bool check(int u) {
  priority_queue<pair<int, int>> pq;
  int allies = s[u];
  set<int> alliance = {u};
  for (int v : g[u])
    pq.push({-s[v], v});
  while (!pq.empty()) {
    int vnxt = pq.top().second;
    pq.pop();
    if (alliance.count(vnxt))
      continue;
    if (s[vnxt] <= allies) {
      allies += s[vnxt];
      alliance.insert(vnxt);
      for (int v : g[vnxt]) {
        if (!alliance.count(v)) {
          pq.push({-s[v], v});
        }
      }
    }
  }
  return alliance.size() == n;
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) {
    scanf("%d", s + i);
  }
  for (int i = 0; i < m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    g[u].push_back(v);
    g[v].push_back(u);
  }
  if (n > 2000) {
    int lo = 1;
    int hi = n;
    int mid;
    while (lo < hi) {
      mid = (lo + hi) / 2;
      if (check(mid)) {
        lo = mid + 1;
      } else {
        hi = mid;
      }
    }
    if (check(lo)) {
      for (int i = 1; i <= n; i++)
        printf("1");
      printf("\n");
    } else {
      for (int i = 1; i <= lo; i++)
        printf("1");
      for (int i = lo + 1; i <= n; i++)
        printf("0");
      printf("\n");
    }
  } else {
    for (int i = 1; i <= n; i++) {
      if (check(i))
        printf("1");
      else
        printf("0");
    }
    printf("\n");
  }
  return 0;
}

Compilation message (stderr)

island.cpp: In function 'bool check(int)':
island.cpp:28:26: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   28 |   return alliance.size() == n;
      |          ~~~~~~~~~~~~~~~~^~~~
island.cpp: In function 'int main()':
island.cpp:31:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |   scanf("%d%d", &n, &m);
      |   ~~~~~^~~~~~~~~~~~~~~~
island.cpp:33:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     scanf("%d", s + i);
      |     ~~~~~^~~~~~~~~~~~~
island.cpp:37:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |     scanf("%d%d", &u, &v);
      |     ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 30
• Subtask 5: 0 / 35