Submission #51439

#	Time	Username	Problem	Language	Result	Execution time	Memory
51439		EntityIT	Watching (JOI13_watching)	C++14	100 / 100	457 ms	32252 KiB

watching

#include<bits/stdc++.h>

using namespace std;

#define int long long

const int N = 2005, inf = 1e18;
int n, p, q, a[N], dp[N][N];

signed main () {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> p >> q;
    if (p >= n || q >= n) return cout << 1, 0;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    sort (a + 1, a + n + 1);
    int l = 1, r = 1000000000;

    while (l < r) {
        int mid = (l + r) >> 1, pter1, pter2;
        pter1 = pter2 = 1;
        memset (dp, 63, sizeof dp);
        dp[0][0] = 0;
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j <= p; ++j) {
                if (dp[i][j] >= inf) continue;
                while (pter1 <= n && a[pter1] <= a[i + 1] + mid - 1) pter1++;
                dp[pter1 - 1][j + 1] = min (dp[pter1 - 1][j + 1], dp[i][j]);
                while (pter2 <= n && a[pter2] <= a[i + 1] + 2 * mid - 1) pter2++;
                dp[pter2 - 1][j] = min (dp[pter2 - 1][j], dp[i][j] + 1);
            }
        }
        bool ok = 0;
        for (int j = 0; j <= p; ++j) {
            if (dp[n][j] <= q) { ok = 1; break; }
        }
        if (ok) r = mid;
        else l = mid + 1;
    }

    cout << l;

    return 0;
}

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