[844_e] Backspace String Compare

TSWeiFramework/Solution.swift

@@ -35,4 +35,23 @@ public extension Solution{
         }
         return (r.2 == Int.min) ? r.0 : r.2
     }
+
+    /**
+     844, Backspace String Compare
+     */
+    func backspaceCompare(_ S: String, _ T: String) -> Bool {
+        return removeBackspace(S) == removeBackspace(T)
+    }
+    private func removeBackspace(_ s: String) -> String{
+        return s.reduce(into: "") { (r, c) in
+            switch c {
+            case _ where c != "#":
+                r.append(c)
+            case "#" where r.count > 0:
+                _ = r.removeLast()
+            default:
+                break
+            }
+        }
+    }
 }

TesoraShot/Solutions/Ray/SolutionsRay.swift

@@ -18,4 +18,9 @@ class SolutionsRay: SolutionsProtocol {
     func thirdMax(_ nums: [Int]) -> Int {
         return -1
     }
+
+    func backspaceCompare(_ S: String, _ T: String) -> Bool {
+        return false
+    }
+
 }

TesoraShot/Solutions/SolutionsProtocol.swift

@@ -58,4 +58,29 @@ protocol SolutionsProtocol {
      - Returns: The third maximum number in this array; the maximum number otherwise.
      */
     func thirdMax(_ nums: [Int]) -> Int
+
+
+    /**
+     # 844. Backspace String Compare
+
+     For example:
+     ```
+     Input: S = "ab#c", T = "ad#c"
+     ```
+     A solution set is:
+     ```
+     Output: true
+     Explanation: Both S and T become "ac".
+     ```
+
+     - Parameters:
+        - S: String with "#" means a backspace character
+        - T: String with "#" means a backspace character
+
+     - SeeAlso:
+     [Link](https://leetcode.com/problems/third-maximum-number/)
+
+     - Returns: they are equal.
+     */
+    func backspaceCompare(_ S: String, _ T: String) -> Bool
 }

TesoraShot/Solutions/Wei/SolutionsWei.swift

@@ -10,6 +10,7 @@ import Foundation
 import TSWeiFramework
 
 class SolutionsWei: SolutionsProtocol {
+
     let s = Solution()
 
     func combinationSum(_ candidates: [Int], _ target: Int) -> [[Int]] {
@@ -19,4 +20,8 @@ class SolutionsWei: SolutionsProtocol {
     func thirdMax(_ nums: [Int]) -> Int {
         return s.thirdMax(nums)
     }
+
+    func backspaceCompare(_ S: String, _ T: String) -> Bool {
+        return s.backspaceCompare(S, T)
+    }
 }