Book allocation problem(please tell the error)

#1
#2

First of all you have not called your function anywhere so it’s not giving any output. You missed a condition in your isValid function, if books[i]>mid then you can directly return false. And in most of your for loops, even while taking input, you have run loop till j<k but it has to be j<n because k is the number of students, not number of books. Here is the corrected code, please refer to it.

#3

the code that you have send is not opening , so can you please send me by other means

#4

import java.util.*;
public class Main {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
int t=sc.nextInt();

  for(int i =0;i<t;i++) {
  int n = sc.nextInt();
  int k =sc.nextInt();
   
  long[] books=new long[n];
  for(int j=0;j<n;j++)
  {
  	books[j]=sc.nextLong();
  }

    System.out.println(binarySearch(books, n, k));
  }

}

public static long binarySearch(long books[], int n, int k) {
long ans = 0, s = 0, e = 0;
long sum = 0;
for (int i = 0; i < n; i++) {
sum += books[i];
//s = Math.max(s, books[i]);

  }
  e = sum;
  while (s <= e) {
  	long mid = (s + e) / 2;
  	if (isValid(books, n, k, mid)) {
  		ans = mid;
  		e = mid - 1;
  	} else {
  		s = mid + 1;
  	}
  }
  return ans;

}

public static boolean isValid(long books[], int n, int k, long ans) {
int students = 1;
long current_page = 0;
for (int i = 0; i < books.length; i++) {
if (books[i] > ans) {

  		return false;
  	}
  	if (current_page + books[i] > ans) {
  		current_page = books[i];
  		students++;
  		if (students > k) {
  			return false;
  		}
  	} else {
  		current_page += books[i];

  	}
  }
  return true;

}

}