Submission #1107450

#	Time	Username	Problem	Language	Result	Execution time	Memory
1107450		Nelt	Watching (JOI13_watching)	C++17	50 / 100	194 ms	31992 KiB

watching

// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
 
#include <bits/stdc++.h>
using namespace std;
 
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pii>
#define db long double
#define vll vector<pll>
#define endl '\n'
#define all(x) x.begin(), x.end()
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
 
#define int long long
 
const int sz = 2e3 + 5;
int n, p, q, dp[sz][sz], a[sz];
 
int check(int w){
    for(int i = 1; i <= n; i++){
        int i1 = 0, i2 = 0;
        int l = 1, r = i - 1;
        while(l <= r){
            int mid = (l + r) / 2;
            if(a[mid] + w <= a[i]){
                i1 = mid;
                l = mid + 1;
            }
            else{
                r = mid - 1;
            }
        }
        l = 1, r = i - 1;
        while(l <= r){
            int mid = (l + r) / 2;
            if(a[mid] + 2 * w <= a[i]){
                i2 = mid;
                l = mid + 1;
            }
            else{
                r = mid - 1;
            }
        }
        for(int j = 1; j <= p; j++){
            // while(i1 + 1 <= n and a[i1 + 1] + w <= a[i]) i1++;
            // while(i2 + 1 <= n and a[i2 + 1] + w * 2 <= a[i]) i2++;
            dp[i][j] = min(dp[i2][j] + 1, dp[i1][j - 1]);
        }
    }
  	ll ans = q + 1;
  	for (ll i = 0; i <= p; i++) ans = min(ans, dp[n][i]);
    return dp[n][p];
}
 
void fmain(){
    fastio;
    cin >> n >> p >> q;
    if(p + q >= n){
        cout << 1;
        return;
    }
    p = min(n, p), q = min(n, q);
    for(int i = 1; i <= n; i++){
        cin >> a[i];
    }
    sort(a + 1, a + n + 1);
    int l = 1, r = 1e18 / (p + q), res = -1;
    while(l <= r){
        int mid = (l + r) / 2;
     	for (ll i = 0; i <= n; i++)
        for (ll j = 0; j <= n; j++) dp[i][j] = 0;
        for(int j = 1; j <= n; j++) dp[j][0] = 1e18;
        if(check(mid) <= q){
            res = mid;
            r = mid - 1;
        }
        else{
            l = mid + 1;
        }
    }
    cout << res;
}
 
signed main(){
    int tmr = 1;
    // cin >> tmr;
    while(tmr--){
        fmain();
    }
}

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