Submission #966399

#	Time	Username	Problem	Language	Result	Execution time	Memory
966399		oviyan_gandhi	Watching (JOI13_watching)	C++14	100 / 100	52 ms	31312 KiB

watching

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

#define N 2001
int n, p, q, a[N], dp[N][N], nw[N], nw2[N]; // next w, next 2w

bool check(int w){
    for (int i = 1, j = 1, k = 1; i <= n; i++){
        while (j < n && a[j+1] - a[i] < w)
            j++;
        while (k < n && a[k+1] - a[i] < 2*w)
            k++;
        nw[i] = j;
        nw2[i] = k;
    }
    for (int i = 0; i <= p; i++){
        for (int j = 0; j <= q; j++){
            dp[i][j] = 0;
            if (i)
                dp[i][j] = max(dp[i][j], nw[dp[i-1][j]+1]);
            if (j)
                dp[i][j] = max(dp[i][j], nw2[dp[i][j-1]+1]);
            if (dp[i][j] == n)
                return true;
        }
    }
    return false;
}

int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> p >> q;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    if ((p + q) >= n){
        cout << "1\n";
        return 0;
    }
    sort(a+1, a+n+1);
    int l = 0, r = 1e9, ans = r;
    while (l <= r){
        int mid = (l+r)/2;
        if (check(mid))
            ans = mid, r = mid-1;
        else l = mid+1;
    }
    cout << ans << '\n';
    return 0;
}

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