Merge pull request #1 from kristoferfannar/72.EditDistance

added golang implementation for edit distance

Author: kristoferfannar

.gitignore

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+# mac user here 👋
+.DS_Store 
+
+.vscode

problems/72. Edit Distance/golang/go.mod

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+module editDistance
+
+go 1.22

problems/72. Edit Distance/golang/main.go

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+// Top down, recursion style Edit Distance implementation
+// While this isn't as fast (and readable) as a simple nested for loop for a bottom up approach
+// (ca 4x faster according to minor testing on my side),
+// I do feel like it is a cooler implementation.
+
+// This is my first leetcode problem,
+// which I solved to get familiar with the algorithm
+//
+
+// Run with:
+// go run .
+// go run . "word1" "word2"
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"time"
+)
+
+// visualizer for fun... it may however be broken. For example
+// EditDistance("park", "spake") shows:
+//   |p a r k
+// s |1 2 3 0
+// p |1 2 3 0
+// a |2 1 2 0
+// k |3 2 2 2
+// e |4 3 3 3
+//
+// which doesn't look correct
+
+func visualizer(D [][]int, word1, word2 string) {
+	for y := range len(word2) + 1 {
+		for x := range len(word1) + 1 {
+			if y == 0 && x == 0 {
+				fmt.Printf("  |")
+			} else if y == 0 {
+				fmt.Printf("%s ", string(word1[x-1]))
+			} else if x == 0 {
+				fmt.Printf("%s |", string(word2[y-1]))
+			} else {
+				fmt.Printf("%d ", D[x][y])
+			}
+			if x == len(word1) {
+				fmt.Println()
+			}
+		}
+	}
+}
+
+func calculate(calc [][]bool, D [][]int, x int, y int, word1 string, word2 string) {
+
+	if x == 0 {
+		D[x][y] = y
+		calc[x][y] = true
+		return
+	}
+
+	if y == 0 {
+		D[x][y] = x
+		calc[x][y] = true
+		return
+	}
+
+	if word1[x-1] == word2[y-1] {
+		lastCalc := calc[x-1][y-1]
+		if !lastCalc {
+			calculate(calc, D, x-1, y-1, word1, word2)
+		}
+		D[x][y] = D[x-1][y-1]
+		calc[x][y] = true
+		return
+	}
+
+	insertCalc := calc[x][y-1]
+	if !insertCalc {
+		calculate(calc, D, x, y-1, word1, word2)
+	}
+	insert := D[x][y-1]
+
+	replaceCalc := calc[x-1][y-1]
+	if !replaceCalc {
+		calculate(calc, D, x-1, y-1, word1, word2)
+	}
+	replace := D[x-1][y-1]
+
+	deleteCalc := calc[x-1][y]
+	if !deleteCalc {
+		calculate(calc, D, x-1, y, word1, word2)
+	}
+	delete := D[x-1][y]
+
+	D[x][y] = min(insert+1, replace+1, delete+1)
+	calc[x][y] = true
+}
+
+func EditDistance(word1 string, word2 string) int {
+	x := len(word1)
+	y := len(word2)
+
+	if x <= 0 && y <= 0 {
+		return 0
+	} else if x <= 0 || y <= 0 {
+		return x + y
+	}
+
+	D := make([][]int, x+1)
+	calc := make([][]bool, x+1)
+
+	for i := range calc {
+		calc[i] = make([]bool, y+1)
+		D[i] = make([]int, y+1)
+	}
+
+	// visualizer(D, word1, word2)
+	calculate(calc, D, x, y, word1, word2)
+
+	if len(word1) <= 50 && len(word2) <= 50 {
+		visualizer(D, word1, word2)
+	}
+	return D[x][y]
+}
+
+func tests() {
+	dna1000_1 := "ggtggttggtcagaaccgtcccgtatgttcataactaggcactagtaccggggccaggacgggagtgcaatagcaagcccttatcaaaaccgtcgcgctaaccacgcaaagatacggtatcacatatgccaagaattggggatgggtattagaatgacctaggtcaacactccttgttagagcgagtggcgtgtgacgtaccacgtcgtacttaactagatcgcttaaagccccgatgtggccacttggaggattcaaaggccctaatgatcctcacacgctaccgaggttgacggcgcttcttgaaaacacaaatttcttggtgacatacgcctacgactcattgtcgtacttttcgtctatcaccaagcgaaacctcccccacttaaccatctatgcgaattgttattcggcaccgccaccgtggaaacccgtcataaaaggaccatgccaaattggtttcatcgacaaagtccattaagttcgatataaacttatttgcagctcgcaagataaaaggctatgtccatgccatgttcggcgcacctctcctcgcgctgtaggacgcaacgttcgttcataatcgagtagtcctgctgcactgatggagccatccattgcagcgtcagcgcttcgactccggcccgctcatcgctagttagctatccgtacagtatcagaacatcttggggcttagtaaagtggtcggatccggtgttttttgcagtagcaaatggtttctaaaaacctgtcggcttttagattttacgatccctcgagtcttcgacttcttcgatcgtcacggtcctaagtgtcttgcgaccaggtatcagtgggcgcgtgcactttttgagttcgaagttagcgagcgtccctagaagtatccaattgcacctgttgaaaggaggaatatcctcaaattttaggaccttttagccttacccatactcgtggtagaagcattcggtcgtcggttagagttccattagtaataaatcgc"
+	dna1000_2 := "aagtggggcagtggctcacacccatcatttggtgctaggcaatatatggtgaaaattcggtgcgggaagccaatcttgatgcagtcaactaaggtaaggctggcatgactagaaagcgttgacggcactacgtccatacatgcagccagtcgagataagtacttatacggttaccatctatgaaccagaccggatgtaatccagattaaacgggattgggtctttgctttcacccgggcttggttagagacagcaccctttcctgattacacctcgcataaaaccctagattttaggacactggacggtcttttcgcgatgcttttggtgtgcgccggacaaaggttataaatggtgtctctagtgaaggacggtttagtcgatgccaacgtgtatcaatgtagggcacggccggaggtctcgctggtattgcatttcgggatccgatgaatatcgtacgatagtagtgtccacagaacctttgtgtagttatacgcgctgtggtaccgatggccatagccgtagtggtccgctttgtgtgctgcgctacctgccggccctttaagggaacacgtgtaagccagttaactgagttcctaacccccaagagcatcgctccgatgtgttacgtactctcgtcactccagagatgcacgctcgactagtggtctggcagttatcggcttcgtgaagtatcgcaagtcttgacgttggactttgggtattataaccaatgtcgtgacgatatcgtgtcctagcgggctacctacatgcgggcggtaatatcgcgaatggccgcccacaagagtagaatcagttttcgtgtcctccttggttttcctgcatcgaatgttagctaggctgggacatcaatatatgtttcgcgcgtctttggtagcttccactcatctaaacattatcctggcctactgaaagtaatttccagggaccaccaacgggtccctggccgtattacccagcatcgtttctcccaggtcaa"
+	dna100_1 := dna1000_1[:100]
+	dna100_2 := dna1000_2[:100]
+
+	start := time.Now()
+	fmt.Printf("EditDistance(): n = %d | %d", 100, EditDistance(dna100_1, dna100_2))
+	end := time.Now()
+	fmt.Printf(" in %v\n", end.Sub(start))
+
+	start = time.Now()
+	fmt.Printf("EditDistance(): n = %d | %d", 1000, EditDistance(dna1000_1, dna1000_2))
+	end = time.Now()
+	fmt.Printf(" in %v\n", end.Sub(start))
+}
+
+func main() {
+	if len(os.Args) == 3 {
+		fmt.Printf("Program arguments %s and %s accepted\n", os.Args[1], os.Args[2])
+		word1 := os.Args[1]
+		word2 := os.Args[2]
+
+		start := time.Now()
+		fmt.Printf("EditDistance(%s, %s) | %d", word1, word2, EditDistance(word1, word2))
+		end := time.Now()
+		fmt.Printf(" in %v\n", end.Sub(start))
+	} else {
+		tests()
+	}
+
+}