增加了find_unique

Author: uuk020

README.md

@@ -17,4 +17,4 @@
 - [series_sum:规律计算题](https://github.com/uuk020/PHPCode/blob/master/series_sum/answer.php)
 - [thirt:13的可分性规则](https://github.com/uuk020/PHPCode/blob/master/thirt/answer.php) 
 - [listSquared:找出一个数是它所有整除的数的平方之和的结果,此结果能够开平方.](https://github.com/uuk020/PHPCode/blob/master/listSquared/answer.php)
-
+- [Find the unique number: 找数组不同的值.](https://github.com/uuk020/PHPCode/blob/master/find_uniq/answer.php)

find_uniq/answer.php

@@ -0,0 +1,16 @@
+<?php
+/**
+ * There is an array with some numbers. All numbers are equal except for one. Try to find it!
+ * findUniq([ 1, 1, 1, 2, 1, 1 ]) === 2
+ * findUniq([ 0, 0, 0.55, 0, 0 ]) === 0.55
+ *
+ * @param array $a
+ * @return void
+ */
+function find_uniq($a) {
+    // 排序从小到大
+    sort($a);
+    // 比较
+    return $a[0] === $a[1] ? end($a) : $a[0];
+}
+