LeetCode 27. Removing Elements

Title Description

27. Remove elements

solution

Solution or speed pointer ： If fast Encountered value is val The elements of , Then skip directly , Otherwise, it will be assigned to slow The pointer , And let slow Take a step forward

however , Notice here and the ordered array de duplication （26. Remove duplicate items from an ordered array ） There is one detail difference in the solution of , We are here to give nums[slow] Assign a value and then give it to slow++, This ensures nums[0…slow-1] Does not contain a value of val The elements of the , The final result is the length of the array slow

class Solution {
    
public:
    int removeElement(vector<int>& nums, int val) {
    
        if (nums.size() == 0) return 0;
        int slow = 0, fast = 0;
        while (fast < nums.size())
        {
    
            if (nums[fast] != val)
            {
    
                nums[slow] = nums[fast];
                slow++;
            }
            fast++;
        }
        return slow;
    }
};