HackerEarth K - Jump problem solution

In this HackerEarth K - Jump problem solution we have given an array A of size N, you can jump from an index i to another index j if  A[j] - A[i] >= K, for j > i. Find the length of the longest sequence of jumps that can be possible in the array. You can start at any index.

HackerEarth K - Jump problem solution.

#include <bits/stdc++.h>

using namespace std;
#define pb push_back
#define MAX5 1000005
int arr[MAX5];
int n,k;
int dp[MAX5];
int n2(){
    int ans = 0;
    for(int i = 0; i < n; i++){
        dp[i] = 1;
    }
    for(int i = 1; i < n; i++){
        for(int j = 0; j < i; j++){
            if(arr[i] >= arr[j] + k){
                dp[i] = max(dp[i], 1 + dp[j]);
            }
        }
    }
    for(int i = 0; i < n; i++){
        ans = max(ans, dp[i]);
    }
    return ans;
}

multiset <int> p;
multiset <int> :: iterator it;

int nlogn(){
    p.clear();
    for(int i=0;i<n;i++)
    {
        int tmp = arr[i];
        it = p.upper_bound(tmp-k);
        if(it == p.end())
        {
            p.insert(tmp);
            continue;
        }
        if(*it > tmp)
        {
            p.erase(it);
            p.insert(tmp);
        }
    }
    return p.size();
}

int main()
{
    cin >> k >> n;
    for(int i = 0; i < n; i++){
        cin >> arr[i];
    }
    cout << nlogn() << endl;
}