week 8 three sum smaller

//Given an array of n integers nums and a target, find the number of index triplets i,j,k with 0 <=i<j<k<n that satisfy the condition 
//nums[i] + nums[j] + nums[k] < target.

public int threeSumSmaller(int [] nums, int target){
     int count = 0;
     Arrays.sort(nums);
     int len = nums.length;
     
     for (int i = 0; i < nums.length - 2; i++){
        int start = i + 1;
        int end = nums.length - 1;
        while(start < end){
           if(nums[i] + nums[start + nums[end] < target){
             count += end - start++;
             }else{
             end--;
             }
            }
           }
          return count;
        }
        
//Summary: pointers
//1. Physical Meaning of Pointers: scanner or fixer
//2.In each iteration, how to deal with fixer? Not scanner
//In iteration, temporarily, you just have one scanner. 
//the function of scanner: lead to the next interation, so we need to decide which pointer should be fixed.