제출 #56871

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
56871		Benq	구경하기 (JOI13_watching)	C++14	100 / 100	85 ms	8956 KiB

watching

#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 / 50
• Subtask 2: 50 / 50