每天一道编程题

• 题目描述
• 样例
• python解法
• C语言解法

题目描述

Given an array containing n distinct numbers taken from 0, 1, 2, …, n, find the one that is missing from the array.

样例

Example 1:

Input: [3,0,1]
Output: 2

Example 2:

Input: [9,6,4,2,3,5,7,0,1]
Output: 8

python解法

class Solution:
    def missingNumber(self, nums: List[int]) -> int:
        req_sum = len(nums)*(len(nums)+1)/2
        act_sum = sum(nums)
        return int(req_sum-act_sum)

Runtime: 156 ms
Memory Usage: 15.2 MB
题后反思：无

C语言解法

int missingNumber(int* nums, int numsSize){
    long sum = 0;
    for (int i=0;i<numsSize;i++)
    {
        sum += nums[i];
    }
    return (int)((numsSize+1)*numsSize/2 - sum);
}

Runtime: 20 ms, faster than 53.38% of C online submissions for Missing Number.
Memory Usage: 7.9 MB, less than 14.29% of C online submissions for Missing Number.
题后反思：无

文中都是我个人的理解，如有错误的地方欢迎下方评论告诉我，我及时更正，大家共同进步