Submission #1281372

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281372		red_souls	Fire (BOI24_fire)	C++20	0 / 100	46 ms	5400 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define task "FIRE"
using namespace std;

const int N = 5e5 + 16;
int n, m, s[N], e[N];

namespace sub6 {

    struct line {
        int l, r, id;

        bool operator < (const line &other) const {
            if (l == other.l) {
                return r > other.r;
            }
            return l < other.l;
        }
    };

    int cnt, result;
    line a[N];
    bool visited[N];

    void solve() {
        for (int i = 1; i <= n; i++) {
            if (s[i] <= e[i]) {
                a[++cnt] = {s[i], e[i], i};
            }
            else {
                a[++cnt] = {s[i], m, i};
                a[++cnt] = {0, e[i], i};
            }
        }
        sort(a + 1, a + 1 + cnt);

        /*
        for (int i = 1; i <= cnt; i++) {
            cout << a[i].l << " " << a[i].r << " " << a[i].id << "\n";
        }
        */

        int curP = 1, p = 0;
        while (p <= m) {
            int r = -1, rId = -1;
            while (curP <= cnt && a[curP].l <= p) {
                if (a[curP].r > r) {
                    r = a[curP].r;
                    rId = curP;
                }
                curP++;
            }
            if (r < p) {
                cout << -1;
                return;
            }
            p = r + 1;
            visited[a[rId].id] = true;
        }

        for (int i = 1; i <= n; i++) {
            if (visited[i]) {
                result++;
            }
        }
        cout << result;
    }
}

int main() {
    ios_base :: sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }

    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> s[i] >> e[i];
    }
    sub6 :: solve();

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 14
• Subtask 2: 0 / 17
• Subtask 3: 0 / 9
• Subtask 4: 0 / 13
• Subtask 5: 0 / 21
• Subtask 6: 0 / 26