Given an array of integers and an integer k, you need to find the number of unique k-diff pairs in the array. Here a k-diff pair is defined as an integer pair (i, j), where i and j are both numbers in the array and their absolute difference is k.
Example 1:
Input: [3, 1, 4, 1, 5], k = 2 Output: 2 Explanation: There are two 2-diff pairs in the array, (1, 3) and (3, 5).Although we have two 1s in the input, we should only return the number of unique pairs.
Example 2:
Input:[1, 2, 3, 4, 5], k = 1 Output: 4 Explanation: There are four 1-diff pairs in the array, (1, 2), (2, 3), (3, 4) and (4, 5).
Example 3:
Input: [1, 3, 1, 5, 4], k = 0 Output: 1 Explanation: There is one 0-diff pair in the array, (1, 1).
Note:
- The pairs (i, j) and (j, i) count as the same pair.
- The length of the array won‘t exceed 10,000.
- All the integers in the given input belong to the range: [-1e7, 1e7].
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 var count:Int = 0
4 if k < 0 {return count}
5 var hm:[Int:Int] = [Int:Int]()
6 let len:Int = nums.count
7 for i in 0..<len
8 {
9 hm[nums[i]] = i
10 }
11 for i in 0..<len
12 {
13 //如果字典包含所请求键的值，则下标返回包含该键的现有值的可选值。否则，下标返回nil：
14 if let keys = hm[nums[i] + k]
15 {
16 if keys != i
17 {
18 count += 1
19 //使用下标语法通过nil为该键指定值来从字典中删除键值对
20 //使用该removeValue(forKey:)方法从字典中删除键值对。hm.removeValue(forKey:key)
21 //此方法删除键值对（如果存在）并返回已删除的值，nil如果不存在值则返回
22 hm[nums[i] + k] = nil
23 }
24 }
25 }
26 return count
27 }
28 }
44ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 guard k >= 0 else {
4 return 0
5 }
6
7 var dict = [Int: Int]()
8 for num in nums {
9 //dict[num] = dict[num] == nil ? 0 : dict[num]! + 1
10 dict[num, default: 0] += 1
11 }
12
13 var res = 0
14 for (num, count) in dict {
15 if k == 0 {
16 if count > 1 {
17 res += 1
18 }
19 } else {
20 if dict[num - k] != nil {
21 res += 1
22 }
23 }
24
25 }
26 return res
27 }
28 }
48ma
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 guard nums.count > 1 else { return 0 }
4 guard k >= 0 else { return 0 }
5
6 var res = 0
7 var dict = [Int: Int]()
8 for n in nums {
9 if let val = dict[n] {
10 dict[n] = val + 1
11 } else {
12 dict[n] = 1
13 }
14 }
15
16 if k == 0 {
17 return dict.reduce(0) { (r, arg1) -> Int in
18 if arg1.value > 1 { return r + 1}
19 return r
20 }
21 } else {
22 for key in dict.keys {
23 if dict.keys.contains(key + k) {
24 res = res + 1
25 }
26 }
27 return res
28 }
29 }
30 }
52ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 guard k >= 0 else {
4 return 0
5 }
6
7 var dict = [Int: Int]()
8 for num in nums {
9 dict[num, default: 0] += 1
10 }
11
12 var res = 0
13 for (num, count) in dict {
14 if k == 0 {
15 if count > 1 {
16 res += 1
17 }
18 } else {
19 if dict[num - k] != nil {
20 res += 1
21 }
22 }
23
24 }
25 return res
26 }
27 }
56ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 var dict = [Int: Bool]()
4
5 if k < 0 {
6 return 0
7 }
8
9 var diff = k < 0 ? -1*k : k
10 var count = 0
11
12
13
14 for num in nums {
15 if !dict.keys.contains(num) {
16 dict[num] = false
17 if diff == 0 { continue }
18 }
19
20 if dict.keys.contains(num-diff) {
21 if dict[num-diff] == false {
22 dict[num-diff] = true
23 count = count + 1
24 }
25
26 }
27 if dict.keys.contains(num+diff) {
28 if dict[num] == false {
29 dict[num] = true
30 count = count + 1
31 }
32 }
33 }
34
35 return count
36 }
37 }
68ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3
4 guard k >= 0 else { return 0 }
5
6 var dict = nums.reduce(into: [Int: Int]()) { dict, num in
7 dict[num, default:0] += 1
8 }
9
10 guard k > 0 else {
11 return dict.reduce(into: 0) { count, numAndCount in
12 if numAndCount.1 > 1 {
13 count += 1
14 }
15 }
16 }
17
18 var totalCount = 0
19 for (num, count) in dict {
20 if dict[num+k, default:0] > 0 {
21 totalCount += 1
22 }
23 if dict[num-k, default: 0] > 0 {
24 totalCount += 1
25 }
26 dict[num] = 0
27 }
28
29 return totalCount
30 }
31 }
76ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3
4 guard k >= 0 else { return 0 }
5
6 var dict = nums.reduce(into: [Int: Int]()) { dict, num in
7 dict[num, default:0] += 1
8 }
9
10 if k == 0 {
11 return dict.values.reduce(into: 0) { total, appearances in
12 if appearances > 1 {
13 total += 1
14 }
15 }
16 }
17
18 return dict.keys.reduce(into: 0) { total, num in
19 if dict[num+k, default:0] > 0 {
20 total += 1
21 }
22 if dict[num-k, default: 0] > 0 {
23 total += 1
24 }
25 dict[num] = 0
26 }
27
28 }
29 }
96ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 guard nums.count > 1 else { return 0}
4 let sortedNums = nums.sorted()
5 var behind = 0
6 var forward = 1
7 var counter = 0
8
9 while forward < nums.count , behind < nums.count {
10 if behind >= forward {
11 forward = behind + 1
12 continue
13 }
14
15 let diff = abs(sortedNums[forward] - sortedNums[behind])
16
17 if diff < k {
18 repeat { forward += 1} while forward < nums.count && sortedNums[forward] == sortedNums[forward-1]
19 continue
20 }
21
22 if diff == k {
23 counter += 1
24 repeat { forward += 1} while forward < nums.count && sortedNums[forward] == sortedNums[forward-1]
25 repeat { behind += 1} while behind < nums.count && sortedNums[behind] == sortedNums[behind-1]
26 continue
27 }
28
29 if diff > k {
30 repeat { behind += 1} while behind < nums.count && sortedNums[behind] == sortedNums[behind-1]
31 continue
32 }
33 }
34 return counter
35 }
36 }
116ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 let nums = nums.sorted()
4 var i = 0
5 var j = 1
6 var res = 0
7 while i < nums.count && j < nums.count {
8 if nums[j] - nums[i] == k {
9 res += 1
10 i += 1
11 j += 1
12 while j < nums.count && nums[j] == nums[j-1] {
13 j += 1
14 }
15 }else if nums[j] - nums[i] < k {
16 j += 1
17 }else {
18 i += 1
19 j = i < j ? j : i+1
20 }
21 }
22 return res
23 }
24 }
132ms
1 class Solution {
2 func findPairs(_ nums: [Int], _ k: Int) -> Int {
3 guard nums.count > 1 else {
4 return 0
5 }
6 var resultSet: [[Int]] = []
7 var sortedNums = nums
8 sortedNums.sort()
9 var firstPointer = 0
10 var secondPointer = 1
11 while secondPointer < sortedNums.count {
12 // print("comparing : \(sortedNums[firstPointer]) and \(sortedNums[secondPointer])")
13 if abs(sortedNums[firstPointer] - sortedNums[secondPointer]) == k {
14 var validList: [Int] = [sortedNums[firstPointer], sortedNums[secondPointer]]
15 // if !resultSet.contains(where: {$0 == validList}) {
16 resultSet.append(validList)
17 // }
18 firstPointer += 1
19 } else if (sortedNums[secondPointer] - sortedNums[firstPointer]) < k {
20 secondPointer += 1
21 } else {
22 firstPointer += 1
23 }
24 if firstPointer == secondPointer {
25 secondPointer += 1
26 }
27 }
28 print("This is the result set : \(resultSet)")
29 var removeIndex:[Int] = []
30 if resultSet.count > 1 {
31 for index in 1..<resultSet.count {
32 // print("index : \(index)")
33 if resultSet[index] == resultSet[index-1] {
34 removeIndex.append(index)
35 }
36 }
37 }
38 while removeIndex.count != 0 {
39 // print("removing \(removeIndex.last) as \(removeIndex)")
40 resultSet.remove(at: removeIndex.last!)
41 let _ = removeIndex.popLast()
42 }
43 return resultSet.count
44 }
45 }
原文地址：https://www.cnblogs.com/strengthen/p/9813030.html
时间： 2024-10-08 06:46:50