Submission #824155

#	Time	Username	Problem	Language	Result	Execution time	Memory
824155		Koyote	Watching (JOI13_watching)	C++14	0 / 100	37 ms	16020 KiB

watching

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

const int N = 2e3 + 2;
int n, p, q, a[N];
int dp[N][N]; // dp[i][j]: number of small cameras needed to take pictures of i events with j big cameras

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n >> p >> q;
    for (int i = 1; i <= n; i++) cin >> a[i];
    sort(a + 1, a + n + 1);

    if (p >= n || q >= n) return cout << 1 << '\n', 0;

    auto binary_func = [&](int x) {
        memset(dp, 0x7f, sizeof(dp));
        dp[0][0] = 0;
        for (int i = 1; i <= n; i++) {
            int sl = 1, bl = 1;
            while (a[i] - a[sl] + 1 > x) sl++;
            while (a[i] - a[bl] + 1 > 2 * x) bl++;
            for (int j = 0; j <= q; j++) {
                dp[i][j] = dp[sl - 1][j] + 1;
                if (j > 0) dp[i][j] = min(dp[i][j], dp[bl - 1][j - 1]);
            }
        }
        for (int j = 0; j <= q; j++) if (dp[n][j] <= p) return true;
        return false;
    };

    int lo = 1, hi = n;
    while (lo <= hi) {
        int mid = (lo + hi) >> 1;
        if (binary_func(mid)) hi = mid - 1;
        else lo = mid + 1;
    }
    cout << lo << '\n';
}

• Subtask 1: 0 / 50
• Subtask 2: 0 / 50