题目

Given N integers, you are supposed to find the smallest positive integer that is NOT in the given list.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N(≤105)N (≤10^5). Then N integers are given in the next line, separated by spaces. All the numbers are in the range of int.

Output Specification:

Print in a line the smallest positive integer that is missing from the input list.

Sample Input:

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2
10
5 -25 9 6 1 3 4 2 5 17

Sample Output:

1
7

题解

思路

  • 题目的意思是
  • 给你一串数
  • 让你从1,2,3,4,5一直到正无穷，找到第一个不在列表里的数
  • 那么只要建立哈希集合，然后照着步骤来就可以了。

数据结构

  • nums 是一个哈希集和，存放所有的数

算法

  • 没啥算法

代码

  • 由于使用Python能够AC，因此只放了Python的题解。
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_ = int(input())
nums = set(list(map(int,input().split())))
for i in range(1,9999999999):
    if i not in nums:
        print(i)
        break