Add problem 72 - Edit Distance

Author: anirudhology

problems/dynamic_programming/edit_distance.go

@@ -0,0 +1,33 @@
+package dynamic_programming
+
+func EditDistance(word1 string, word2 string) int {
+	// Lengths of strings
+	m, n := len(word1), len(word2)
+	// Lookup table to store the minimum operations count
+	lookup := make([][]int, m+1)
+	for i := range lookup {
+		lookup[i] = make([]int, n+1)
+		for j := range lookup[i] {
+			lookup[i][j] = 0
+		}
+	}
+	// Base initialization
+	for i := 0; i <= m; i++ {
+		lookup[i][0] = i
+	}
+	for j := 0; j <= n; j++ {
+		lookup[0][j] = j
+	}
+	// Populate the remaining table
+	for i := 1; i <= m; i++ {
+		for j := 1; j <= n; j++ {
+			// If both characters are same, we don't have to do anything
+			cost := 0
+			if word1[i-1] != word2[j-1] {
+				cost = 1
+			}
+			lookup[i][j] = min(cost+lookup[i-1][j-1], 1+min(lookup[i-1][j], lookup[i][j-1]))
+		}
+	}
+	return lookup[m][n]
+}

tests/dynamic_programming/edit_distance_test.go

@@ -0,0 +1,41 @@
+package dynamic_programming_test
+
+import (
+	"testing"
+
+	"github.com/anirudhology/leetcode-go/problems/dynamic_programming"
+)
+
+func TestMinDistanceEmptyStrings(t *testing.T) {
+	result := dynamic_programming.EditDistance("", "")
+	if result != 0 {
+		t.Errorf("Expected 0, got %d", result)
+	}
+}
+
+func TestMinDistanceOneEmptyString(t *testing.T) {
+	if result := dynamic_programming.EditDistance("hello", ""); result != 5 {
+		t.Errorf("Expected 5, got %d", result)
+	}
+	if result := dynamic_programming.EditDistance("", "java"); result != 4 {
+		t.Errorf("Expected 4, got %d", result)
+	}
+}
+
+func TestMinDistanceSameStrings(t *testing.T) {
+	if result := dynamic_programming.EditDistance("same", "same"); result != 0 {
+		t.Errorf("Expected 0, got %d", result)
+	}
+}
+
+func TestMinDistanceDifferentStrings(t *testing.T) {
+	if result := dynamic_programming.EditDistance("horse", "ros"); result != 3 {
+		t.Errorf("Expected 3, got %d", result)
+	}
+	if result := dynamic_programming.EditDistance("intention", "execution"); result != 5 {
+		t.Errorf("Expected 5, got %d", result)
+	}
+	if result := dynamic_programming.EditDistance("flaw", "lawn"); result != 2 {
+		t.Errorf("Expected 2, got %d", result)
+	}
+}