Submission #907507

#	Time	Username	Problem	Language	Result	Execution time	Memory
907507		typ_ik	Watching (JOI13_watching)	C++17	100 / 100	289 ms	19096 KiB

watching

#include <bits/stdc++.h>

#define ll long long
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define watch(x) cout << (#x) << " : " << x << '\n'
#define boost ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

using namespace std;  

const int N = 2222;
const int INF = 2e9 + 128;
int dp[N][N]; 
int a[N];

void solve() { 
    int n, p, q;
    cin >> n >> p >> q;
    for (int i = 1; i <= n; i++)
        cin >> a[i];

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

    auto check = [&](int w) -> bool {   
        for (int i = 0; i <= n+2; i++)
            for (int c = 0; c <= p+2; c++)    
                dp[i][c] = INF;
        for (int i = 0; i <= p; i++) 
            dp[0][i] = 0;

        int j0 = 0, j1 = 0; 

        for (int i = 1; i <= n; i++) {
            // place w.
            while (j0 + 1 <= n && a[j0 + 1] - a[i] + 1 <= w)
                j0++;
            while (j1 + 1 <= n && a[j1 + 1] - a[i] + 1 <= 2*w)
                j1++;  

            for (int lp = 0; lp <= p; lp++)
                dp[j0][lp] = min(dp[j0][lp], dp[i-1][lp+1]);
            
            for (int lp = 0; lp <= p; lp++)
                dp[j1][lp] = min(dp[j1][lp], dp[i-1][lp]+1); 
        }  

        for (int i = 0; i <= p; i++)
            if (dp[n][i] <= q)
                return true;

        return false; 
    };   

    int l = 0, r = 1e9 + 128;
    while (l + 1 < r) {
        int m = (l + r) >> 1;
        if (check(m))
            r = m;
        else 
            l = m;
    }

    cout << r << '\n';
}

main() { 
    boost;  
    solve();
    return 0;
}

Compilation message (stderr)

watching.cpp:71:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   71 | main() {
      | ^~~~

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