P10779 [HackerEarth] sock scramble
普及
题目描述

1) Rama is late to college as usual. As he went on to pull a pair of socks , he found that the number of socks was odd. Though he had a pair of socks to put on he was curious on finding the socks whose pair was missing. The colours of socks are can take any integer value >0. Can you help him find out the colour of the socks whose pair was missing in the most efficient way ?
Input:
t- no of testcases
n- no of socks
n numbers each separated by a space follow where every number denotes the colour of the socks.

constraints

1 ≤ t ≤ 20
1<n<50
1<a[i]<100000 , a[i] denotes the color of a sock

SAMPLE INPUT
1
5
2 2 1 1 4

SAMPLE OUTPUT
4

输入格式

见题面

输出格式

见题面

样例输入
20 3 88 7439 88 5 8801 8801 2157 4596 4596 3 1377 5701 1377 9 1860 1860 4126 72 72 6086 6086 7394 7394 5 985 985 9625 1899 1899 7 6013 6013 146 146 7606 3026 7606 11 3973 3973 4322 4322 7112 7112 6404 6404 1250 814 1250 9 9189 9189 5161 5161 2022 2022 5274 2273 5274 5 6860 2691 2691 6736 6736 11 1918 1918 2373 2373 643 643 5875 5875 2175 1449 2175 5 2122 2122 4241 3371 4241 3 6749 6672 6672 9 2023 2023 739 739 4366 5324 5324 7774 7774 9 1800 1226 1226 7221 7221 1158 1158 9495 9495 11 1819 1819 6205 3169 3169 1601 1601 5811 5811 1643 1643 5 514 3765 3765 8037 8037 3 7026 8888 8888 11 1392 1392 3873 3873 6898 6898 2617 2617 7446 8463 7446 11 183 183 7861 7861 4994 8026 8026 3352 3352 5813 5813 5 6358 6358 5628 4394 5628
样例输出
7439 2157 5701 4126 9625 3026 814 2273 6860 1449 3371 6749 4366 1800 6205 514 7026 8463 4994 4394