27. Remove elements

Title Description ：
Give you an array nums And a value val, You need In situ Remove all values equal to val The elements of , And return the new length of the array after removal .

Don't use extra array space , You have to use only O(1) Additional space and In situ Modify input array .

class Solution {
    
public:
    int removeElement(vector<int>& nums, int val) {
    
    	// Use two subscripts , Traverse array first 
		// If it is not the target value , Just cover the element forward to the array , It is equivalent to deleting the element 
		// Returns the subscript 
        int index = 0; 
        for (int i = 0; i < nums.size(); ++i) 
        {
      
            if (val != nums[i]) 
            {
     
                nums[index++] = nums[i]; 
            }
        }
        return index;
    }
};