3 Sum Smaller

Given an integer array nums and an integer target, return the number of triplets (i, j, k) such that 0 <= i < j < k < n and nums[i] + nums[j] + nums[k] < target.

Example 1:

• Input: nums = [-2,0,1,3], target = 2
• Output: 2

// The greatest will be either in the first or at the end, so we will fill it from the end.
class Solution {
    public int searchTriplets(int[] arr, int target) {
        var count = 0;
        Arrays.sort(arr);
        for (int i = 0; i < arr.length; i ++) {
        var targetSum = target - arr[i];
        var l = i + 1;
        var r = arr.length - 1;
        while (l < r) {
            if (arr[l] + arr[r] < targetSum) {
            count += (r - l);
            l ++;
            } else {
            r --;
            }
        }
        }
        return count;
  }
}