https://hack.codingblocks.com/contests/c/452/408
#include<bits/stdc++.h>
using namespace std;
// Utility function to check if current minimum value
// is feasible or not.
bool isPossible(int arr[], int n, int m, int curr_min)
{
int studentsRequired = 1;
int curr_sum = 0;
// iterate over all books
for (int i = 0; i < n; i++)
{
// check if current number of pages are greater
// than curr_min that means we will get the result
// after mid no. of pages
if (arr[i] > curr_min)
return false;
// count how many students are required
// to distribute curr_min pages
if (curr_sum + arr[i] > curr_min)
{
// increment student count
studentsRequired++;
// update curr_sum
curr_sum = arr[i];
// if students required becomes greater
// than given no. of students,return false
if (studentsRequired > m)
return false;
}
// else update curr_sum
else
curr_sum += arr[i];
}
return true;
}
// function to find minimum pages
int findPages(int arr[], int n, int m)
{
long long sum = 0;
// return -1 if no. of books is less than
// no. of students
if (n < m)
return -1;
// Count total number of pages
for (int i = 0; i < n; i++)
sum += arr[i];
// initialize start as 0 pages and end as
// total pages
int start = 0, end = sum;
int result = INT_MAX;
// traverse until start <= end
while (start <= end)
{
// check if it is possible to distribute
// books by using mid as current minimum
int mid = (start + end) / 2;
if (isPossible(arr, n, m, mid))
{
// if yes then find the minimum distribution
result = min(result, mid);
// as we are finding minimum and books
// are sorted so reduce end = mid -1
// that means
end = mid - 1;
}
else
// if not possible means pages should be
// increased so update start = mid + 1
start = mid + 1;
}
// at-last return minimum no. of pages
return result;
}
// Drivers code
int main()
{
//Number of pages in books
int n,m;
cin>>n>>m;
int arr[n];
for(int i=0;i<n;i++)
cin>>arr[i];
cout << findPages(arr, n, m) << endl;
return 0;
}