PROG-1107: Jump

#include <bits/stdc++.h>

using namespace std;
const int N = 1e6;
const int INF = 1e9;
using pii = pair <int, int>;
pii ar[N+10]; // value, position
bool pst[N+10];
int n, K, P;

bool compare(pii a, pii b){
    return a.first > b.first;
}

bool check(){
    int k = 0, prev = -1;
    for(int i=1;i<=n;i++){
        if(pst[i]){
            if(prev == -1){
                k ++;
                prev = i;
                if(k > K) return false;
            }
            else if(i - prev + 1 == P){
                prev = -1;
            }
            else if(i - prev + 1 > P){
                k ++;
                prev = i;
                if(k > K) return false;
            }
        }
    }
    return true;
}

int main(){

   scanf("%d%d%d", &n, &K, &P);

    for(int i=1;i<=n;i++){
        int x;
        scanf("%d", &x);
        ar[i] = {x, i};
    }

    sort(ar+1, ar+n+1, compare);

    int l = 1, r = n, mx = -INF;
    while(l <= r){
        int mid = (l + r) / 2;
        for(int i = 1; i <= n; i ++) pst[i] = false;
        for(int i = 1; i <= mid; i ++) pst[ ar[i].second ] = true;
        if(!check()){
            mx = max(mx, ar[mid].first);
            r = mid - 1;
        }
        else l = mid + 1;
    }

    if(mx == -INF) printf("%d", ar[n].first);
    else printf("%d", mx);

    return 0;
}