Submission #80475

#	Time	Username	Problem	Language	Result	Execution time	Memory
80475		mra2322001	Watching (JOI13_watching)	C++14	100 / 100	329 ms	16964 KiB

watching

#include <bits/stdc++.h>
#define f0(i, n) for(int i(0); i < (n); i++)
#define f1(i, n) for(int i(1); i <= n; i++)

using namespace std;
typedef long long ll;
const int N = 2002;

int n, p, q, a[N];
int f[N][N], d1[N], d2[N];

bool solve(int w){
    memset(f, -1, sizeof(f));
    ///sort(a + 1, a + n + 1);
    f1(i, n){
        d1[i] = d2[i] = 0;
        d1[i] = lower_bound(a + 1, a + n + 1, a[i] - w + 1) - a;
        d2[i] = lower_bound(a + 1, a + n + 1, a[i] - 2*w + 1) - a;
    }
    /// f[i][j];
    f0(j, p + 1) f[0][j] = q;
    f1(i, n){
        f0(j, p + 1){
            if(j > 0){
                int k1 = d1[i];
                f[i][j] = f[max(k1 - 1, 0)][j - 1];
                f[i][j] = max(f[max(0, d2[i] - 1)][j] - 1, f[i][j]);
            }
            else{
                f[i][j] = f[max(d2[i] - 1, 0)][j] - 1;
            }
        }
    }
    f0(j, p + 1) if(f[n][j] >= 0) return 1;
    return 0;
}

int main(){
    ios_base::sync_with_stdio(0);


    cin >> n >> p >> q;
    f1(i, n) cin >> a[i];

    if(p + q >= n){
        cout << 1; return 0;
    }
    sort(a + 1, a + n + 1);

    int l = 1, r = 1e9 + 2, ans = -1;
    while(l <= r){
        int m = (l + r)/2;
        if(solve(m)) r = m - 1, ans = m;
        else l = m + 1;
    }
    cout << ans;
}

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