原文地址：https://www.cnblogs.com/strengthen/p/10283261.html
Shuffle a set of numbers without duplicates.
Example:
// Init an array with set 1, 2, and 3.
int[] nums = {1,2,3};
Solution solution = new Solution(nums);
// Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must equally likely to be returned.
solution.shuffle();
// Resets the array back to its original configuration [1,2,3].
solution.reset();
// Returns the random shuffling of array [1,2,3].
solution.shuffle();
打乱一个没有重复元素的数组。
示例:
// 以数字集合 1, 2 和 3 初始化数组。
int[] nums = {1,2,3};
Solution solution = new Solution(nums);
// 打乱数组 [1,2,3] 并返回结果。任何 [1,2,3]的排列返回的概率应该相同。
solution.shuffle();
// 重设数组到它的初始状态[1,2,3]。
solution.reset();
// 随机返回数组[1,2,3]打乱后的结果。
solution.shuffle();
676ms
1 class Solution { 2 var nums:[Int] 3 var oriNums:[Int] 4 init(_ nums: [Int]) { 5 self.nums = nums 6 self.oriNums = nums 7 } 8 9 /** Resets the array to its original configuration and return it. */ 10 func reset() -> [Int] { 11 return self.oriNums 12 } 13 14 /** Returns a random shuffling of the array. */ 15 func shuffle() -> [Int] { 16 for i in 0..<nums.count/2 17 { 18 var t:Int = Int.random(in:0..<(nums.count)) 19 //法1： 20 //(nums[i], nums[t]) = (nums[t],nums[i]) 21 //法2： 22 nums.swapAt(i,t); 23 } 24 return nums 25 } 26 } 27 28 /** 29 * Your Solution object will be instantiated and called as such: 30 * let obj = Solution(nums) 31 * let ret_1: [Int] = obj.reset() 32 * let ret_2: [Int] = obj.shuffle() 33 */ 34
704ms
1 class Solution { 2 3 var original: [Int] 4 var shuffable: [Int] 5 init(_ nums: [Int]) { 6 self.original = nums 7 self.shuffable = nums 8 } 9 10 /** Resets the array to its original configuration and return it. */ 11 func reset() -> [Int] { 12 return original 13 } 14 15 /** Returns a random shuffling of the array. */ 16 func shuffle() -> [Int] { 17 shuffable.shuffle() 18 return shuffable 19 } 20 } 21 22 /** 23 * Your Solution object will be instantiated and called as such: 24 * let obj = Solution(nums) 25 * let ret_1: [Int] = obj.reset() 26 * let ret_2: [Int] = obj.shuffle() 27 */
760ms
1 class Solution { 2 var a = [Int]() 3 init(_ nums: [Int]) { 4 a = nums 5 } 6 7 /** Resets the array to its original configuration and return it. */ 8 func reset() -> [Int] { 9 return a 10 } 11 12 /** Returns a random shuffling of the array. */ 13 func shuffle() -> [Int] { 14 if a == []{return a} 15 return shuffle0() 16 } 17 func shuffle0() -> [Int] { 18 var data:[Int] = a 19 for i in 0..<a.count { 20 let index = Int.random(in: 0 ... i) 21 if index != i { 22 (data[i] , data[index]) = (data[index] , data[i]) 23 } 24 } 25 return data 26 } 27 } 28 29 /** 30 * Your Solution object will be instantiated and called as such: 31 * let obj = Solution(nums) 32 * let ret_1: [Int] = obj.reset() 33 * let ret_2: [Int] = obj.shuffle() 34 */
828ms
1 class Solution { 2 var interges: [Int] 3 init(_ nums: [Int]) { 4 self.interges = nums 5 } 6 /** Resets the array to its original configuration and return it. */ 7 func reset() -> [Int] { 8 return interges 9 } 10 /** Returns a random shuffling of the array. */ 11 func shuffle() -> [Int] { 12 var shuffled = interges 13 var cursorL = shuffled.startIndex 14 let cursorR = shuffled.index(before: interges.endIndex) 15 while cursorL < cursorR { 16 let steps = shuffled.distance(from: cursorL, to: cursorR) 17 let randomStep = Int.random(in: 0...steps) 18 let offsetIndex = shuffled.index(cursorL, offsetBy: randomStep) 19 shuffled.swapAt(cursorL, offsetIndex) 20 shuffled.formIndex(after: &cursorL) 21 } 22 return shuffled 23 } 24 }
860ms
1 class Solution { 2 var num: [Int] 3 4 init(_ nums: [Int]) { 5 self.num = nums 6 } 7 8 /** Resets the array to its original configuration and return it. */ 9 func reset() -> [Int] { 10 return self.num 11 } 12 13 /** Returns a random shuffling of the array. */ 14 func shuffle() -> [Int] { 15 return self.num.shuffled() 16 } 17 }