oj.uz

Submission #56871

# Submission time Handle Problem Language Result Execution time Memory
56871 2018-07-13T01:40:08 Z Benq Watching (JOI13_watching) C++14
100 / 100
 85 ms 8956 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;

int N,P,Q, dp[2001][2001], nexLarge[2001], nexSmall[2001];
vi A;

bool ok(int w) {
    F0R(i,P+1) F0R(j,Q+1) dp[i][j] = 0;
    nexLarge[N] = nexSmall[N] = N;
    F0Rd(i,N) {
        nexLarge[i] = nexLarge[i+1];
        while ((ll)A[i]+2*w-1 < A[nexLarge[i]-1]) nexLarge[i] --;
        nexSmall[i] = nexSmall[i+1];
        while ((ll)A[i]+w-1 < A[nexSmall[i]-1]) nexSmall[i] --;
    }
    F0R(i,P+1) F0R(j,Q+1) {
        if (dp[i][j] >= N) return 1;
        if (i < P) dp[i+1][j] = max(dp[i+1][j],nexSmall[dp[i][j]]);
        if (j < Q) dp[i][j+1] = max(dp[i][j+1],nexLarge[dp[i][j]]);
    }
    return 0;
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> N >> P >> Q; A.resize(N);
    F0R(i,N) cin >> A[i];
    sort(all(A));
    Q = min(Q,N);
    P = min(P,N-Q);
    int lo = 1, hi = 1000000000;
    while (lo < hi) {
        int mid = (lo+hi)/2;
        if (ok(mid)) hi = mid;
        else lo = mid+1;
    }
    cout << lo;
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 504 KB Output is correct
2 Correct 2 ms 504 KB Output is correct
3 Correct 2 ms 504 KB Output is correct
4 Correct 4 ms 816 KB Output is correct
5 Correct 3 ms 816 KB Output is correct
6 Correct 3 ms 816 KB Output is correct
7 Correct 3 ms 816 KB Output is correct
8 Correct 3 ms 816 KB Output is correct
9 Correct 3 ms 816 KB Output is correct
10 Correct 2 ms 816 KB Output is correct
11 Correct 3 ms 816 KB Output is correct
12 Correct 2 ms 816 KB Output is correct
13 Correct 2 ms 816 KB Output is correct
14 Correct 2 ms 816 KB Output is correct
15 Correct 3 ms 816 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 816 KB Output is correct
2 Correct 2 ms 816 KB Output is correct
3 Correct 53 ms 4600 KB Output is correct
4 Correct 27 ms 8952 KB Output is correct
5 Correct 4 ms 8952 KB Output is correct
6 Correct 3 ms 8952 KB Output is correct
7 Correct 4 ms 8952 KB Output is correct
8 Correct 17 ms 8952 KB Output is correct
9 Correct 18 ms 8952 KB Output is correct
10 Correct 30 ms 8956 KB Output is correct
11 Correct 17 ms 8956 KB Output is correct
12 Correct 85 ms 8956 KB Output is correct
13 Correct 3 ms 8956 KB Output is correct
14 Correct 4 ms 8956 KB Output is correct
15 Correct 3 ms 8956 KB Output is correct