oj.uz

Submission #371548

# Submission time Handle Problem Language Result Execution time Memory
371548 2021-02-26T21:29:48 Z ritul_kr_singh Watching (JOI13_watching) C++17
100 / 100
 427 ms 30188 KB 
//#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define sp << " " <<
#define nl << "\n"

int n, p, q, a[2001];

bool possible(int w){
    int dp[n+1][p+1];
    for(int i=0; i<=n; ++i){
        for(int j=0; j<=p; ++j){
            dp[i][j] = i ? 1e10 : 0;
        }
    }
    for(int i=1; i<=n; ++i){
        int f0 = upper_bound(a, a+n, max(0LL, a[i]-w)) - a - 1;
        int f1 = upper_bound(a, a+n, max(0LL, a[i]-2*w)) - a - 1;
        int g0 = 0, g1 = 0;
        while(g0+1<i and a[g0+1]+w-1<a[i]) ++g0;
        while(g1+1<i and a[g1+1]+2*w-1<a[i]) ++g1;
        assert(f0==g0 and f1==g1);
        for(int j=0; j<=p; ++j){
            // use
            if(j){
                dp[i][j] = min(dp[i][j], dp[f0][j-1]);
            }
            // don't
            dp[i][j] = min(dp[i][j], dp[f1][j] + 1);
        }
    }
    return dp[n][p]<=q;
}

signed main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    cin >> n >> p >> q;
    a[0] = 0;
    for(int i=1; i<=n; ++i) cin >> a[i];
    sort(a+1, a+n+1);
    if(p>n or q>n){
        cout << 1 nl;
        return 0;
    }
    int low = 1, high = 1e9;
    while(low<high){
        int mid = (low+high)/2;
        if(possible(mid)) high = mid;
        else low = mid+1;
    }
    cout << low nl;
}

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 512 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 376 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 2 ms 364 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 359 ms 23916 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 59 ms 620 KB Output is correct
8 Correct 89 ms 2284 KB Output is correct
9 Correct 222 ms 12140 KB Output is correct
10 Correct 427 ms 30188 KB Output is correct
11 Correct 90 ms 1772 KB Output is correct
12 Correct 259 ms 15756 KB Output is correct
13 Correct 59 ms 748 KB Output is correct
14 Correct 69 ms 748 KB Output is correct
15 Correct 73 ms 748 KB Output is correct