Missing number
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Problem Description
There is a permutation without two numbers in it, and now you know what numbers the permutation has. Please find the two numbers it lose.
Input
There is a number T shows there are T test cases below. (T≤10)
For each test case , the first line contains a integers n , which means the number of numbers the permutation has. In following a line , there are n distinct postive integers.(1≤n≤1,000)
Output
For each case output two numbers , small number first.
Sample Input
2
3
3 4 5
1
1
Sample Output
1 2
2 3
题意
找出一个数列中缺的两个数。
分析
本来没啥好说的，记录完了之后O(n)扫描一遍即可，启发就是一种简单的O(1)的算法也要多多注意下。
1 | Sum(n) =n*(n+1)/2 |