Submission #574131

#	Time	Username	Problem	Language	Result	Execution time	Memory
574131		eecs	Stranded Far From Home (BOI22_island)	C++17	100 / 100	456 ms	28296 KiB

island

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

const int maxn = 200010;
int n, m, a[maxn], fa[maxn], sum[maxn];
bool vis[maxn], ans[maxn];
vector<int> G[maxn];
set<pair<int, int>> S;

int find(int x) {
    return x == fa[x] ? x : fa[x] = find(fa[x]);
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    cin >> n >> m;
    vector<array<int, 2>> V;
    for (int i = 1; i <= n; i++) {
        cin >> a[i], V.push_back({a[i], i});
    }
    while (m--) {
        int u, v;
        cin >> u >> v;
        G[u].push_back(v), G[v].push_back(u);
    }
    for (int i = 1; i <= n; i++) {
        S.emplace(a[i], i);
    }
    sort(V.begin(), V.end());
    iota(fa + 1, fa + n + 1, 1);
    copy(a + 1, a + n + 1, sum + 1);
    int lst = 0;
    for (int i = 0; i < V.size(); i++) {
        vis[V[i][1]] = 1;
        for (int j : G[V[i][1]]) if (vis[j]) {
            int x = find(V[i][1]), y = find(j);
            if (x ^ y) fa[y] = x, sum[x] = min((int)1e9, sum[x] + sum[y]);
        }
        if (i + 1 < V.size() && V[i][0] == V[i + 1][0]) continue;
        while (!S.empty() && V[i][0] == S.begin()->first) {
            int x = S.begin()->second;
            int y = prev(lower_bound(V.begin(), V.end(), array<int, 2>{sum[find(x)] + 1, 0}))->at(0);
            S.erase(S.begin());
            if (V[i][0] < y) S.emplace(y, x);
            else if (i + 1 == V.size()) ans[x] = 1;
        }
    }
    for (int i = 1; i <= n; i++) {
        cout << (ans[i] ? '1' : '0');
    }
    return 0;
}

Compilation message (stderr)

island.cpp: In function 'int main()':
island.cpp:33:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |     for (int i = 0; i < V.size(); i++) {
      |                     ~~^~~~~~~~~~
island.cpp:39:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |         if (i + 1 < V.size() && V[i][0] == V[i + 1][0]) continue;
      |             ~~~~~~^~~~~~~~~~
island.cpp:45:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |             else if (i + 1 == V.size()) ans[x] = 1;
      |                      ~~~~~~^~~~~~~~~~~
island.cpp:32:9: warning: unused variable 'lst' [-Wunused-variable]
   32 |     int lst = 0;
      |         ^~~

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