Create: 72-Edit-Distance.swift

Author: Ykhan799

swift/72-Edit-Distance.swift

@@ -0,0 +1,45 @@
+class Solution {
+    func minDistance(_ word1: String, _ word2: String) -> Int {
+        // No operations needed if strings match
+        if word1 == word2 {
+            return 0
+        }
+        
+        let m = word1.count, n = word2.count
+        
+        // if one word has no characters, min operations is length of other word
+        if m == 0 {
+            return n
+        }
+        if n == 0 {
+            return m
+        }
+        
+        var prev = 0
+        var curr = Array(repeating: 0, count: n + 1)
+        
+        // convert the strings into an array
+        let newWord1 = Array(word1)
+        let newWord2 = Array(word2)
+        
+        for j in 1...n {
+            curr[j] = j
+        }
+        
+        for i in 1...m {
+            var prev = curr[0]
+            curr[0] = i
+            for j in 1...n {
+                let temp = curr[j]
+                if newWord1[i - 1] == newWord2[j - 1] {
+                    curr[j] = prev
+                }
+                else {
+                    curr[j] = min(prev, min(curr[j - 1], curr[j])) + 1
+                }
+                prev = temp
+            }
+        }
+        return curr[n]
+    }
+}