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arrayssummax

maximum no. of elements in an array having sum less than or equal to k

I want to find the maximum no. of elements in a given positive integer array such that their sum is less than or equal to a given no. k. For example, I have an array 

[3,4,7,2,6,5,1] and k=6;

The Answer is 3 as 1,2,3 are maximum elements to give sum 6.

Solution

  • Sort the array, count the number of elements, then start summing elements sequentially until their sum is greater than k or you have gone through each element, then subtract 1 from the count if the sum is greater than k

    Pseudocode:

        let k=6
    sort the array
    [1,2,3,4,5,6,7]
    let sum=0
    let count=7 //(7 elements in the array)
    for (i=0;i<7;i++) {
        sum+=array[i];
        if (sum>k)
            break;
    }
    if (sum>k)
    i--;

    i is the max number of elements.