oj.uz

Submission #371551

# Submission time Handle Problem Language Result Execution time Memory
371551 2021-02-26T21:31:12 Z ritul_kr_singh Watching (JOI13_watching) C++17
100 / 100
 446 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 364 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 364 KB Output is correct
5 Correct 1 ms 512 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 364 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 2 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 380 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 26 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 358 ms 23916 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 60 ms 620 KB Output is correct
8 Correct 88 ms 2284 KB Output is correct
9 Correct 214 ms 12140 KB Output is correct
10 Correct 446 ms 30188 KB Output is correct
11 Correct 85 ms 1772 KB Output is correct
12 Correct 253 ms 15852 KB Output is correct
13 Correct 57 ms 620 KB Output is correct
14 Correct 71 ms 620 KB Output is correct
15 Correct 76 ms 748 KB Output is correct