Submission #583263

#	Time	Username	Problem	Language	Result	Execution time	Memory
583263		Jomnoi	Teleporters (IOI08_teleporters)	C++17	25 / 100	333 ms	19784 KiB

teleporters

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

const int MAX_N = 1e6 + 5;

int W[MAX_N], E[MAX_N];
int id[MAX_N];
int parent[MAX_N], sz[MAX_N];

int find_parent(int u) {
    if(u == parent[u]) {
        return u;
    }
    return parent[u] = find_parent(parent[u]);
}

void merge(int u, int v) {
    u = find_parent(u), v = find_parent(v);
    if(u == v) {
        return;
    }

    sz[u] += sz[v];
    parent[v] = u;
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    int N, M;
    cin >> N >> M;

    for(int i = 1; i <= N; i++) {
        cin >> W[i] >> E[i];
    }

    for(int i = 1; i <= N; i++) {
        id[i] = i;
        parent[i] = i;
        sz[i] = 1;
    }

    sort(id + 1, id + N + 1, [&](const int &a, const int &b) {
        return W[a] < W[b];
    });

    for(int l = 1, r = 2; l <= N; l++) {
        while(r <= N and W[id[r]] <= E[id[l]] and E[id[r]] > E[id[l]]) {
            merge(id[l], id[r]);
            r++;
        }
    }

    int ans = 0;
    for(int i = 1; i <= N; i++) {
        if(find_parent(i) == i) {
            if(sz[i] > 1) {
                ans += 4;
            }
            else if(M > 0) {
                M--;
                ans += 4;
            }
            else {
                ans++;
            }
        }
    }

    while(M >= 2) {
        ans += 4;
        M -= 2;
    }
    ans += M;

    cout << ans;
    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 0 / 5
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• Subtask 14: 5 / 5
• Subtask 15: 0 / 5
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• Subtask 17: 5 / 5
• Subtask 18: 0 / 5
• Subtask 19: 0 / 5
• Subtask 20: 0 / 5