0163-missing-ranges

bofeizhu · Aug 20, 2018 · 450f165 · 450f165
1 parent 0f825f1
commit 450f165
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Showing 2 changed files with 7 additions and 8 deletions.
diff --git a/0163-missing-ranges.playground/Contents.swift b/0163-missing-ranges.playground/Contents.swift
@@ -10,17 +10,16 @@ import XCTest
 
 /// Approach: Iteration
 func findMissingRanges(_ nums: [Int], _ lower: Int, _ upper: Int) -> [String] {
-    var numbers = [lower - 1]
-    numbers.append(contentsOf: nums)
-    numbers.append(upper + 1)
     var result: [String] = []
-    for i in 0..<numbers.count - 1 {
-        let difference = numbers[i + 1] - numbers[i]
+    for i in -1..<nums.count {
+        let current = i == -1 ? lower - 1 : nums[i]
+        let next = i + 1 < nums.count ? nums[i + 1] : upper + 1
+        let difference = next - current
         guard difference > 1 else { continue }
         if difference == 2 {
-            result.append(String(numbers[i] + 1))
+            result.append(String(current + 1))
         } else {
-            result.append(String(numbers[i] + 1) + "->" + String(numbers[i + 1] - 1))
+            result.append(String(current + 1) + "->" + String(next - 1))
         }
     }
     return result

diff --git a/README.md b/README.md
@@ -54,7 +54,7 @@ You can visit the pages below to search problems by company tags. Then come back
 33 | [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0033-search-in-rotated-sorted-array.playground/Contents.swift) | Binary Search
 66 | [Plus One](https://leetcode.com/problems/plus-one/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0066-plus-one.playground/Contents.swift) | Math
 84 | [Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0084-largest-rectangle-in-histogram.playground/Contents.swift) | Stack
-163 | [Missing Ranges](https://leetcode.com/problems/missing-ranges/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0163-missing-ranges.playground/Contents.swift) | BFS
+163 | [Missing Ranges](https://leetcode.com/problems/missing-ranges/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0163-missing-ranges.playground/Contents.swift) | Iteration
 200 | [Number of Islands](https://leetcode.com/problems/number-of-islands/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0200-number-of-islands.playground/Contents.swift) | BFS
 482 | [License Key Formatting](https://leetcode.com/problems/license-key-formatting/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0482-license-key-formatting.playground/Contents.swift) | String
 681 | [Next Closest Time](https://leetcode.com/problems/next-closest-time/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0681-next-closest-time.playground/Contents.swift) | Simulation