KMAX2 - Editorial

editorial
, ,
21

Can someone please tell me what’s wrong with my Code

import java.util.;
import java.lang.;
import java.io.*;

class Codechef
{
public static void main (String[] args) throws java.lang.Exception
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
long tcases = Long.parseLong(br.readLine());
while(tcases–>0)
{
String str = br.readLine();
String str1[] = str.trim().split(" “);
long N = Long.parseLong(str1[0]);
long K = Long.parseLong(str1[1]);
String s = br.readLine();
String s1[] = s.trim().split(” ");
long arr[] = new long[(int)N];
for(long i=0;i<N;i++)
arr[(int)i] = Long.parseLong(s1[(int)i]);
long max = Integer.MIN_VALUE;
for(long i=0;i<N;i++)
{
if(arr[(int)i]>max)
max=arr[(int)i];
}
int ctr =0;
for(long i=K-1;i<N;i++)
if(arr[(int)i]==max)
ctr+=(N-i);
System.out.println(ctr);
}
}
}

22 
#include <iostream>
typedef long long ll;
using namespace std;

int main() {
	ll t;
	cin>>t;
	while(t)
	{
	    ll n,k;
	    cin>>n>>k;
	    ll arr[n];
	    for(ll j=1;j<=n;j++)
	    {
	        cin>>arr[j];
	    }
	    ll mx=arr[0];
	    for(ll j=1;j<=n;j++)
	    {
	        if(mx<arr[j])
	        {
	            mx=arr[j];
	        }
	    }
	    cout<<mx<<endl;
	  for(ll j=k;j<=n;j++)
	  {
	      if(mx==arr[j])
	      {
	        cout<<n-j+1<<endl;
	        break;
	      }
	  }
	  
	    t--;
	}
	return 0;
}
bro can you please help me why this code is giving wrong answer
23

Out of bounds access on sample test input:

[simon@simon-laptop][20:40:11]
[~/devel/hackerrank/otherpeoples]>./compile-latest-cpp.sh 
Compiling akshansh_1-KMAX2.cpp
+ g++ -std=c++14 akshansh_1-KMAX2.cpp -O3 -g3 -Wall -Wextra -Wconversion -DONLINE_JUDGE -D_GLIBCXX_DEBUG -fsanitize=undefined -ftrapv -fno-sanitize-recover
+ set +x
Successful
[simon@simon-laptop][20:40:55]
[~/devel/hackerrank/otherpeoples]>echo "1                 
5 3
1 2 3 4 5
" | ./a.out
akshansh_1-KMAX2.cpp:20:24: runtime error: index 5 out of bounds for type 'long long int [*]'
1 Like
24

understood, thanks.

25

Ohh got it dude.

26

#include<bits/stdc++.h>
using namespace std;
#define ll long long int
int main()
{
ll t,n,k,z,l;
cin>>t;
while(t–)
{
cin>>n>>k;
ll a[n];
ll max1=INT_MIN;
for(ll i=0;i<n;i++)
{
cin>>a[i];
}
for(ll i=0;i<n;i++)
{
if(a[i]>max1)
{
max1=a[i];
l=i;
}
}
ll z=l-(k-1);
if(z<0)
cout<<“0”<<endl;
else
{
int m=n-(l+1);
cout<<m+1<<endl;
}

}
return 0;

}
please help me to find out error in my code it is giving wrong anwer but according to me it seems to be right for everytest case.

27

@nitishsharma12 You are finding the maximum element and also storing its index. But there can be a situation where the maximum element is present more than once in the array. Consider Array [5,5,5,5,5] or [3,4 5,6 2,1,6,3,1,3].

1 Like
28

ohh i understand where is my error thanku so much.

29

why my code not working?
#include<bits/stdc++.h>
using namespace std;

int main() {

long long t;
cin>>t;

long long sum=-1e9;
while(t–)
{

 long long  int  n,k;
    cin>>n>>k;
   vector<long long>v(n);
    
    for(int i=1;i<=n;i++){
    cin>>v[i];
    sum=max(sum,v[i]);
}
   long long  ans=0;
    
    for(int i=k;i<=n;i++)
    {
        if(sum==v[i])
        {
            ans+=n+1-i;
        }
    }
    cout<<ans<<endl;
}
return 0;

}

31

you realize there can be more than 1 value that is equal to max_element right

1 2 5 5 5 5

what do u think the answer is to this test case for k = 3? its 10 i hope you can figure out now

32

if array size is 5 and k = 3 and arr[]: 5 5 5 5 5
Correct o/p is 6 not 3

33

your code is fine. simply return long long instead of int.

34

A Note to Editorial Solution -

@janmansh You should provide most efficient solution. Why you are using space O(N) if you can do it O(1)?

Check this out - time complexity O(N) Single pass. Space complexity O(1).

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

int main() {
int t;
cin>>t;
while(t–){
int n,k;
cin>>n>>k;
int a,max;
cin>>a;
max = a;
long long int count = 0;
if(k == 1) count = n;

    for(int i=1;i<n;i++){
        cin>>a;
        if(a > max){
            max = a;
            //initialise count..
            if(i >= k-1) {
                count = n-i;
            }
        } else if(a == max && i >= k-1) {
            count += n-i; 
        }
    }
    cout<<count<<endl;
}
return 0;

}