Submission #228359

#	Time	Username	Problem	Language	Result	Execution time	Memory
228359		Nayna	Watching (JOI13_watching)	C++14	50 / 100	1094 ms	31744 KiB

watching

#include <bits/stdc++.h>

using namespace std;
const int mxn = 2e3+5;
typedef long long ll;
const ll inf = 1e16;
ll arr[mxn];
ll dp[mxn][mxn];
ll n, P, Q;

bool solve(ll w)
{
    for(int i = 0; i <= n; i++)
        for(int r = 0; r <= n; r++) dp[i][r] = inf;
    dp[0][0] = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int r = 0; r <= P; r++)
        {
            int x = upper_bound(arr+1, arr+n+1, arr[i]-w)-arr-1;
            int y = upper_bound(arr+1, arr+n+1, arr[i]-w-w)-arr-1;
            if(r) dp[i][r] = min(dp[i][r], dp[x][r-1]);
            dp[i][r] = min(dp[i][r], dp[y][r]+1);
        }
    }
    for(int i = 0; i <= n; i++)
        if(dp[n][i]<=Q) return true;
    return false;
}
int main()
{

    cin >> n >> P >> Q;

    P = min(n, P);
    Q = min(n, Q);

    for(int i = 1; i <= n; i++) cin >> arr[i];

    sort(arr+1, arr+n+1);

    ll lo = 1, hi = 1e9+5, ans = inf;

    while(lo<=hi)
    {
        ll mid = (lo+hi)>>1;
        if(solve(mid))
        {
            hi = mid-1;
            ans = min(ans, mid);
        }
        else lo = mid+1;
    }
    cout << ans << '\n';
    return 0;
}

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