Remove Element 题解
题目来源：https://leetcode.com/problems/remove-element/description/
Description
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.
Solution
class Solution {
public:
int removeElement(vector<int>& nums, int val) {
if (nums.empty())
return 0;
int id = 0;
for (int i = 0; i < nums.size(); i++) {
if (nums[i] != val)
nums[id++] = nums[i];
}
return id;
}
};
解题描述
这道题题意是删除一个数组中指定的元素。想法是用一个标记位id作为要保留的元素的下标，从前往后扫描数组，得到一个要保留的元素就把该元素放到nums[id]，且id++。