// // 136-e4.swift // LeetCode // // Created by nuomi1 on 2018/12/21. // // Single Number // https://leetcode.com/explore/interview/card/top-interview-questions-easy/92/array/549/ // https://leetcode.com/problems/single-number/ // 只出现一次的数字 // https://leetcode-cn.com/leetbook/read/top-interview-questions-easy/x21ib6/ // https://leetcode-cn.com/problems/single-number/ // MARK: Bit Manipulation func singleNumber(_ nums: [Int]) -> Int { // 异或运算 // a ^ 0 = a // a ^ a = 0 // a ^ b ^ a = a ^ a ^ b = 0 ^ b = b return nums.reduce(0) { $0 ^ $1 } }