Submission #637915

#	Time	Username	Problem	Language	Result	Execution time	Memory
637915		tvladm2009	Watching (JOI13_watching)	C++14	100 / 100	130 ms	16016 KiB

watching

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int MAX_N = 2 * 1e3;

int a[MAX_N + 1];
int dp[MAX_N + 1][MAX_N + 1];

int n, p, q;

bool check(int guess) {
    memset(dp, 0, sizeof(dp));
    int j = 1, k = 1;
    for (int i = 1; i <= n; i++) {
        while (a[i] - a[j] >= guess) {
            j++;
        }
        while (a[i] - a[k] >= 2 * guess) {
            k++;
        }
        for (int l = 0; l <= min(i, p); l++) {
            dp[i][l] = dp[k - 1][l] + 1;
            if (l != 0) {
                dp[i][l] = min(dp[i][l], dp[j - 1][l - 1]);
            }
        }
    }
    return (dp[n][min(n, p)] <= q);
}

int cb() {
    int l = 1, r = 1e9, sol = -1;
    while (l <= r) {
        int mid = (l + r) / 2;
        if (check(mid)) {
            sol = mid;
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }
    return sol;
}

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

    cin >> n >> p >> q;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    sort(a + 1, a + n + 1);

    int ans = cb();
    cout << ans;

    return 0;
}

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