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➤微信公众号：山青咏芝（shanqingyongzhi）
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Alice has a hand of cards, given as an array of integers.
Now she wants to rearrange the cards into groups so that each group is size W, and consists of W consecutive cards.
Return true if and only if she can.
Example 1:
Input: hand = [1,2,3,6,2,3,4,7,8], W = 3 Output: true Explanation: Alice'shandcan be rearranged as[1,2,3],[2,3,4],[6,7,8].
Example 2:
Input: hand = [1,2,3,4,5], W = 4 Output: false Explanation: Alice'shandcan't be rearranged into groups of4.
Note:
1 <= hand.length <= 100000 <= hand[i] <= 10^91 <= W <= hand.length
爱丽丝有一手（hand）由整数数组给定的牌。
现在她想把牌重新排列成组，使得每个组的大小都是 W，且由 W 张连续的牌组成。
如果她可以完成分组就返回 true，否则返回 false。
示例 1：
输入：hand = [1,2,3,6,2,3,4,7,8], W = 3
输出：true
解释：爱丽丝的手牌可以被重新排列为 [1,2,3]，[2,3,4]，[6,7,8]。
示例 2：
输入：hand = [1,2,3,4,5], W = 4 输出：false 解释：爱丽丝的手牌无法被重新排列成几个大小为 4 的组。
提示：
1 <= hand.length <= 100000 <= hand[i] <= 10^91 <= W <= hand.length
240ms
1 class Solution { 2 func isNStraightHand(_ hand: [Int], _ W: Int) -> Bool { 3 guard hand.count % W == 0 else { return false } 4 var modulus = Array(repeating: 0, count: W) 5 for i in 0..<hand.count { 6 modulus[hand[i]%W] += 1 7 } 8 for i in 0..<modulus.count-1 { 9 if modulus[i] != modulus[i+1] { 10 return false 11 } 12 } 13 return true 14 } 15 }
300ms
1 class Solution { 2 func isNStraightHand(_ hand: [Int], _ W: Int) -> Bool { 3 if W == 0 { return true } 4 if hand.count % W != 0 { return false } 5 6 var map = [Int: Int]() 7 for h in hand { map[h, default: 0] += 1 } 8 let sortedHand = Array(Set<Int>(hand)).sorted() 9 if sortedHand.count < W { return false } 10 11 for i in 0 ... sortedHand.count - W { 12 let cti = map[sortedHand[i]]! 13 if cti == 0 { continue } 14 map[sortedHand[i]]! -= cti 15 for j in (i+1)..<(W+i) { 16 if map[sortedHand[j]]! < cti { return false } 17 if sortedHand[j] != sortedHand[j-1] + 1 { return false } 18 map[sortedHand[j]]! -= cti 19 } 20 } 21 22 return map.values.filter{ $0 > 0 }.count == 0 23 } 24 }
356ms
1 class Solution { 2 func isNStraightHand(_ hand: [Int], _ W: Int) -> Bool { 3 guard hand.count % W == 0 else { return false } 4 let hand = hand.sorted() 5 var dict = hand.reduce(into: [Int: Int]()){ $0[$1, default: 0] += 1 } 6 for n in hand { 7 guard dict[n, default: 0] > 0 else { continue } 8 for w in 0..<W { 9 dict[n+w, default: 0] -= 1 10 if dict[n+w, default: 0] < 0 { return false } 11 } 12 } 13 return dict.filter{ $0.value > 0 }.isEmpty 14 } 15 }
Runtime: 372 ms
Memory Usage: 19.5 MB
1 class Solution { 2 func isNStraightHand(_ hand: [Int], _ W: Int) -> Bool { 3 var c:[Int:Int] = [Int:Int]() 4 var hand = hand.sorted(by:<) 5 for i in hand 6 { 7 c[i,default:0] += 1 8 } 9 var start:[Int] = [Int]() 10 var last_checked:Int = -1 11 var opened:Int = 0 12 var nums = Set(c.keys).sorted(by:<) 13 for key in nums 14 { 15 if opened > 0 && key > last_checked + 1 || opened > c[key,default:0] 16 { 17 return false 18 } 19 start.append(c[key,default:0] - opened) 20 last_checked = key 21 opened = c[key,default:0] 22 if start.count == W 23 { 24 opened -= start.removeFirst() 25 } 26 } 27 return opened == 0 28 } 29 }
376ms
1 class Solution { 2 func isNStraightHand(_ hand: [Int], _ W: Int) -> Bool { 3 guard hand.count % W == 0 else { return false } 4 let limit = 1_000_000_000 5 var cache: [Int: Int] = [Int: Int]() 6 for card in hand { 7 cache[card, default: 0] += 1 8 } 9 10 var sortedKeys = cache.keys.sorted() 11 while !cache.isEmpty { 12 let first = sortedKeys.first! 13 for i in first..<first+W { 14 guard let value = cache[i] else { return false } 15 cache[i] = value - 1 16 if cache[i] == 0 { 17 cache.removeValue(forKey: i) 18 if let index = sortedKeys.index(of: i) { 19 sortedKeys.remove(at: index) 20 } 21 } 22 } 23 } 24 return true 25 } 26 }
540ms
1 class Solution { 2 func isNStraightHand(_ hand: [Int], _ W: Int) -> Bool { 3 if hand.count % W != 0 { return false } 4 let hand = hand.sorted() 5 let list = DoublyLinkedList(hand) 6 7 while !list.isEmpty { 8 var count = W 9 var node = list.head.next 10 var prevVal = -1 11 while count > 0 && !list.isEmpty && node !== list.tail { 12 let val = node!.val 13 if prevVal >= 0 { 14 if val == prevVal { 15 node = node!.next 16 } else if (val - 1) != prevVal { 17 return false 18 } else { 19 prevVal = val 20 node = node!.next 21 list.delete(node!.prev!) 22 count -= 1 23 } 24 } else { 25 prevVal = val 26 list.delete(node!) 27 count -= 1 28 node = list.head.next 29 } 30 } 31 if count > 0 { return false } 32 } 33 return true 34 } 35 } 36 37 class DoublyLinkedList { 38 var head = Node(0) 39 var tail = Node(0) 40 41 init() { 42 head.next = tail 43 tail.prev = head 44 } 45 46 init(_ arr: [Int]) { 47 head.next = tail 48 tail.prev = head 49 for el in arr { 50 append(el) 51 } 52 } 53 54 func append(_ val: Int) { 55 let node = Node(val) 56 if isEmpty { 57 head.next = node 58 node.next = tail 59 node.prev = head 60 tail.prev = node 61 } else { 62 tail.prev?.next = node 63 node.next = tail 64 node.prev = tail.prev 65 tail.prev = node 66 } 67 } 68 69 func delete(_ node: Node) { 70 node.prev?.next = node.next 71 node.next?.prev = node.prev 72 } 73 74 var isEmpty: Bool { 75 return head.next === tail 76 } 77 78 func printL() { 79 var node = head.next 80 while node !== tail { 81 print("(node!.val)", terminator: "->") 82 node = node!.next 83 } 84 print("") 85 } 86 } 87 88 class Node { 89 var val: Int 90 var next: Node? 91 weak var prev: Node? 92 93 init(_ val: Int) { 94 self.val = val 95 } 96 }