Submission #986208

#	Time	Username	Problem	Language	Result	Execution time	Memory
986208		Khanhcsp2	Watching (JOI13_watching)	C++14	50 / 100	246 ms	31836 KiB

watching

#include <bits/stdc++.h>
#define el '\n'
#define fi first
#define sc second
#define int ll
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
const int mod=1e9+7;
const int N=2e3+11;
int n, x, y, a[N], dp[N][N];
bool check(int w)
{
    for(int i=1;i<=n;i++) for(int j=0;j<=x;j++) dp[i][j]=1e9;
    for(int i=0;i<=x;i++) dp[0][i]=0;
    for(int i=1;i<=n;i++)
    {
        int pos1=lower_bound(a+1, a+n+1, a[i]-w+1)-a;
        int pos2=lower_bound(a+1, a+n+1, a[i]-2*w+1)-a;
        dp[i][0]=min(dp[i][0], dp[pos2][0]+1);
        for(int j=1;j<=x;j++) dp[i][j]=min({dp[i][j], dp[pos1-1][j-1], dp[pos2-1][j]+1});
    }
    for(int i=0;i<=x;i++) if(dp[n][i]<=y) return 1;
    return 0;
}
void sol()
{
    cin >> n >> x >> y;
    for(int i=1;i<=n;i++) cin >> a[i];
    sort(a+1, a+n+1);
    if(n<=x+y)
    {
        cout << 1;
        return;
    }
    int l=1, r=1e9+11, ans=1e9+11;
    while(l<=r)
    {
        int mid=(l+r)/2;
        if(check(mid))
        {
            ans=min(ans, mid);
            r=mid-1;
        }
        else l=mid+1;
    }
    cout << ans;
}
signed main()
{
//    freopen("divisor.INP", "r", stdin);
//    freopen("divisor.OUT", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t=1;
    //cin >> t;
    while(t--)
    {
        sol();
    }
}

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