Add minimum edit distance for strings

Author: Luisa Herrmann

Minimum Edit Distance/MinimumEditDistance.swift

@@ -0,0 +1,27 @@
+extension String {
+    
+    public func minimumEditDistance(other: String) -> Int {
+        let m = self.characters.count
+        let n = other.characters.count
+        var matrix = [[Int]](count: m+1, repeatedValue: [Int](count: n+1, repeatedValue: 0))
+        
+        for index in 1...m {
+            matrix[index][0]=index
+        }
+        for index in 1...n {
+            matrix[0][index]=index
+        }
+        
+        for (i, selfChar) in self.characters.enumerate() {
+            for (j, otherChar) in other.characters.enumerate() {
+                if otherChar == selfChar {
+                    matrix[i+1][j+1] = matrix[i][j]
+                } else {
+                    matrix[i+1][j+1] = min(matrix[i][j]+1, matrix[i+1][j]+1, matrix[i][j+1]+1)
+                }
+                
+            }
+        }
+        return matrix[m][n]
+    }
+}