Length of Smallest Subsequence such that sum of elements is greater than equal to K

Given an array arr[] of size N and a number K, the task is to find the length of the smallest subsequence such that the sum of the subsequence is greater than or equal to number K.

Example:

Input: arr[] = {2, 3, 1, 5, 6, 3, 7, 9, 14, 10, 2, 5}, K = 35
Output: 4
Smallest subsequence with the sum greater than or equal to the given sum K is {7, 9, 14, 10}

Input: arr[] = {1, 2, 2, 2, 3, 4, 5, 4, 7, 6, 5, 12}, K = 70
Output:-1
Subsequence with sum greater than equal to the given sum is not possible.

Approach:



Below is the implementation of above approach.

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ implementation to find length of smallest
// subsequence such that sum of elements
// is greater than equal to given number K
  
#include <bits/stdc++.h>
using namespace std;
  
// Function to find the smallest
// subsequence such that sum of elements
// is greater than equal to given number K
int lengthOfSmallestSubsequence(int K, vector<int> v)
{
    // Initialize priority queue
    priority_queue<int> pq;
  
    // Loop to insert all elements into
    // the priority queue
    for (int i = 0; i < v.size(); i++) {
        pq.push(v[i]);
    }
    int sum = 0, count = 0;
  
    // Loop to find the smallest
    // subsequence such that sum of elements
    // is greater than equal to given number K
    while (!pq.empty() && sum < K) {
        sum += pq.top();
        pq.pop();
        count++;
    }
    // If sum is less then K
    // then return -1 else return count.
    if (sum < K) {
        return -1;
    }
    return count;
}
  
// Driver code
int main()
{
  
    vector<int> v{ 2, 3, 1, 5,
                   6, 3, 7, 9,
                   14, 10, 2, 5 };
    int K = 35;
  
    cout << lengthOfSmallestSubsequence(K, v);
  
    return 0;
}
chevron_right

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java implementation to find length of smallest
// subsequence such that sum of elements
// is greater than equal to given number K
import java.util.*;
  
class GFG
{
  
// Function to find the smallest
// subsequence such that sum of elements
// is greater than equal to given number K
static int lengthOfSmallestSubsequence(int K, int []v)
{
    // Initialize priority queue
    Queue<Integer> pq = 
            new PriorityQueue<Integer>(Collections.reverseOrder());
  
    // Loop to insert all elements into
    // the priority queue
    for (int i = 0; i < v.length; i++) 
    {
        pq.add(v[i]);
    }
    int sum = 0, count = 0;
  
    // Loop to find the smallest
    // subsequence such that sum of elements
    // is greater than equal to given number K
    while (!pq.isEmpty() && sum < K)
    {
        sum += pq.peek();
        pq.remove();
        count++;
    }
      
    // If sum is less then K
    // then return -1 else return count.
    if (sum < K) 
    {
        return -1;
    }
    return count;
}
  
// Driver code
public static void main(String[] args)
{
    int []v = { 2, 3, 1, 5,
                6, 3, 7, 9,
                14, 10, 2, 5 };
    int K = 35;
    System.out.print(lengthOfSmallestSubsequence(K, v));
}
}
  
// This code is contributed by Rajput-Ji
chevron_right

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 implementation to find length of smallest
# subsequence such that sum of elements
# is greater than equal to given number K
  
# Function to find the smallest
# subsequence such that sum of elements
# is greater than equal to given number K
def lengthOfSmallestSubsequence(K, v):
      
    # Initialize priority queue
    pq = []
  
    # Loop to insert all elements into
    # the priority queue
    for i in v:
        pq.append(i)
    pq.sort()
  
    sum = 0
    count = 0
  
    # Loop to find the smallest
    # subsequence such that sum of elements
    # is greater than equal to given number K
    while (len(pq) > 0 and sum < K):
        sum += pq[-1]
        del pq[-1]
        count += 1
      
    # If sum is less then K
    # then return -1 else return count.
    if (sum < K):
        return -1
    return count
  
# Driver code
v = [2, 3, 1, 5,
    6, 3, 7, 9,
    14, 10, 2, 5]
K = 35
  
print(lengthOfSmallestSubsequence(K, v))
  
# This code is contributed by mohit kumar 29
chevron_right

Output:
4

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.




Recommended Posts:

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.



Improved By : mohit kumar 29, Rajput-Ji

Article Tags :