top of page
Search

Minimum Operations to Reduce X to Zero

You are given an integer array nums and an integer x. In one operation, you can either remove the leftmost or the rightmost element from the array nums and subtract its value from x. Note that this modifies the array for future operations.

Return the minimum number of operations to reduce x to exactly 0 if it's possible, otherwise, return -1.

Example 1:

Input: nums = [1,1,4,2,3], x = 5 
Output: 2 
Explanation: The optimal solution is to remove the last two elements to reduce x to zero. 

Example 2:

Input: nums = [5,6,7,8,9], x = 4 Output: -1 

Example 3:


Input: nums = [3,2,20,1,1,3], x = 10 
Output: 5 
Explanation: The optimal solution is to remove the last three elements and the first two elements (5 operations in total) to reduce x to zero. 

Constraints:

  • 1 <= nums.length <= 105

  • 1 <= nums[i] <= 104

  • 1 <= x <= 109

Solution:


class Solution {
    public int minOperations(int[] nums, int x) 
    {
        int target = 0,totalsum=0;
	for (int num : nums) 
	{
	     totalsum+= num;
	}
	target = totalsum-x;
	if (target == 0) return nums.length;  
	Map<Integer, Integer> map = new HashMap<>();
	map.put(0, -1);
	int sum = 0;
	int res = Integer.MIN_VALUE;

	for (int i = 0; i < nums.length; ++i) 
	{
	     sum += nums[i];
	     if (map.containsKey(sum - target)) 
	     {
	      res = Math.max(res, i - map.get(sum - target));
	     }
	     map.put(sum, i);
	}
       return res == Integer.MIN_VALUE ? -1 : nums.length - res;
    }
}


60 views0 comments

Recent Posts

See All

A string s is called good if there are no two different characters in s that have the same frequency. Given a string s, return the minimum number of characters you need to delete to make s good. The f

The numeric value of a lowercase character is defined as its position (1-indexed) in the alphabet, so the numeric value of a is 1, the numeric value of b is 2, the numeric value of c is 3, and so on.

bottom of page