Remove Element
Loop invariant
Setup a wall, on the left side of the wall are the elements which do not contain the target.
When a new element comes and it does not equal to the target, enlarge the space on the left side of the wall, and move the new element into the left side of the wall.
Source code Read on Github
1 public class Solution {
2 public int removeElement(int[] A, int elem) {
3 // IMPORTANT: Please reset any member data you declared, as
4 // the same Solution instance will be reused for each test case.
5 if(A.length == 0) return 0;
6
7 int len = 0;
8
9 for(int i = 0; i< A.length; i++){
10 if(A[i] != elem) A[len++] = A[i];
11 }
12
13
14 return len;
15 }
16 }