首页 > itarticle > leetcode(27) remove element 解法：

leetcode(27) remove element 解法：

admin 11月 29, 2020 0

Given an array and a value, remove all instances of that value in-place and return the new length. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory. The order of elements can be changed. It doesn’t matter what you leave beyond the new length.

Example:

Given nums = [3,2,2,3], val = 3, Your function should return length = 2, with the first two elements of nums being 2.

解法：

此题与26题类似，同样两个指针，快指针用于遍历数组，慢指针用于覆盖指定值，当快指针的值和给定值不同，我们就把慢指针处的值用快指针的值覆盖，并将慢指针加1，快指针加1。代码如下：

class :
    def removeElement(self, nums, val):
        """
        :type nums: List[int]
        :type val: int
        :rtype: int
        """
        if(len(nums) == 0):
            return 0;
        p = 0;
        q = 0;
        while(q<len(nums)):
            if(nums[q] != val):
                nums[p] = nums[q];
                p+=1;
                q+=1;
            else:
                q+=1;
        return p;