Submission #792932

#	Time	Username	Problem	Language	Result	Execution time	Memory
792932		Cookie	Watching (JOI13_watching)	C++14	100 / 100	734 ms	16052 KiB

watching

#include<bits/stdc++.h>
#include<fstream>
using namespace std;
ifstream fin("FEEDING.INP");
ofstream fout("FEEDING.OUT");
#define sz(a) (int)a.size()
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
const ld PI = 3.14159265359;
using u128 = __uint128_t;
const int x[4] = {1, -1, 0, 0};
const int y[4] = {0, 0, 1, -1};
const ll mod = 1e9 + 7, inf = 1e9;
const int mxn = 3e5 + 5;
int n, p, q;
int dp[2005][2005], a[2005];
bool ck(int mid){
    forr(i, 1, n + 2){
        forr(j, 0, p + 1){
            dp[i][j] = inf;
        }
    }
    dp[1][0] = 0;
    for(int i = 1; i <= n; i++){
        for(int j = 0; j <= p; j++){
            if(dp[i][j] == inf)continue;
            if(j != p){
                int idlw = upper_bound(a + 1, a + n + 1, a[i] + mid - 1) - a;
                dp[idlw][j + 1] = min(dp[idlw][j + 1], dp[i][j]);
            }
            int idhg = upper_bound(a + 1, a + n + 1, a[i] + 2 * mid - 1) - a;
            dp[idhg][j] = min(dp[idhg][j], dp[i][j] + 1);
            
        }
    }
    for(int i = 0; i <= p; i++){
        if(dp[n + 1][i] <= q)return(1);
    }
    return(0);
}
signed main()
{
     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> p >> q; p = min(p, n);
    for(int i = 1; i <= n; i++){
        cin >> a[i];
    }
    sort(a + 1, a + n + 1);
    
    
    int l = 0, r = 5e8, ans = -1;
    while(l <= r){
        int mid = (l + r) >> 1;
        if(ck(mid)){
            ans = mid; r = mid - 1;
        }else{
            l = mid + 1;
        }
    }
    cout << ans;
    
    return(0);
}

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