Submission #963512

#	Time	Username	Problem	Language	Result	Execution time	Memory
963512		BhavayGoyal	Watching (JOI13_watching)	C++14	100 / 100	318 ms	32200 KiB

watching

#include <bits/stdc++.h>
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

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

#define int long long
#define ld long double
#define ar array
#define vi vector<int>
#define vii vector<vector<int>>
#define pii pair<int, int>
#define pb push_back
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define endl "\n"

const int MOD = 1e9+7;
const int inf = 1e9;
const int linf = 1e18;

const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());


// -------------------------------------------------- Main Code --------------------------------------------------

int dp[2005][2005];
int n, nxtP[2005], nxtQ[2005], arr[2005];

int sol(int idx, int p) {
    if (idx >= n) return 0;
    if (dp[idx][p] != -1) return dp[idx][p];
    int ans = inf;
    if (p) ans = min(ans, sol(nxtP[idx]+1, p-1));
    ans = min(ans, sol(nxtQ[idx]+1, p) + 1);
    return dp[idx][p] = ans;
}

void sol() {
    int p, q; cin >> n >> p >> q;
    p = min(p, n); q = min(q, n);

    for (int i = 0; i < n; i++) cin >> arr[i];
    sort(arr, arr+n);

    auto fiss = [&](int mid) {
        for (int i = 0; i <= n; i++) for (int j = 0; j <= p; j++) dp[i][j] = -1;
        for (int i = 0; i < n; i++) {
            nxtP[i] = upper_bound(arr, arr+n, arr[i]+mid-1) - arr - 1;
            nxtQ[i] = upper_bound(arr, arr+n, arr[i]+2*mid-1) - arr - 1;
        }
        
        return (sol(0, p) <= q);
    };

    int i = 1, j = inf, ans = inf;
    while (i <= j) {
        int mid = (i+j)/2;
        if (fiss(mid)) ans = mid, j = mid-1;
        else i = mid+1;
    }
    cout << ans << endl;
}

signed main () {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int t = 1;
    // cin >> t; 
    while (t--) {
        sol();
    }
    return 0;
}

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