Initial commit

.gitignore

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+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/

.golangci.yml

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+run:
+  concurrency: 4
+  tests: true
+
+linters-settings:
+  errcheck:
+    check-type-assertions: false
+    check-blank: true
+  govet:
+    check-shadowing: true
+  golint:
+    min-confidence: 0.8
+  goimports:
+    local-prefixes: github.com/rohitsubedi/levenshtein
+  gocyclo:
+    min-complexity: 10
+  maligned:
+    suggest-new: true
+  dupl:
+    threshold: 75
+  goconst:
+    min-len: 3
+    min-occurrences: 3
+  depguard:
+    list-type: blacklist
+    include-go-root: false
+  misspell:
+    locale: US
+    ignore-words:
+      - someword
+  lll:
+    line-length: 120
+    tab-width: 1
+  unused:
+    check-exported: false
+  unparam:
+    check-exported: false
+  nakedret:
+    max-func-lines: 20
+  prealloc:
+    simple: true
+    range-loops: true # Report preallocation suggestions on range loops, true by default
+    for-loops: false # Report preallocation suggestions on for loops, false by default
+linters:
+  enable-all: true
+  fast: false

.travis.yml

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+language: go
+
+go_import_path: github.com/rohitsubedi/levenshtein
+
+before_install:
+  - export GO111MODULE=on
+
+go:
+  - 1.13.x
+  - 1.14.x
+  - 1.15.x
+  - tip
+
+install:
+  - go get github.com/stretchr/testify@v1.6.1
+  - go get github.com/golangci/golangci-lint/cmd/golangci-lint
+
+script:
+  - make check

LICENSE

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+MIT License
+
+Copyright (c) 2020 Rohit Subedi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

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+check: test lint
+
+test: ## Runs the unit tests.
+	@go test $(PKG_NAME)
+
+lint: ## Runs the linter.
+	@golangci-lint run

README.md

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+# levenshtein

go.mod

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+module github.com/rohitsubedi/levenshtein
+
+go 1.15
+
+require github.com/stretchr/testify v1.6.1

go.sum

@@ -0,0 +1,11 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

levenshtein.go

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+package levenshtein
+
+const increment = 1
+
+func GetLevenshteinDistance(str1, str2 []rune, caseSensitive bool) int {
+	rows := len(str2)
+	cols := len(str1)
+
+	// If one of the given string is empty, Levenshtein distance is the max length of two string
+	if rows == 0 || cols == 0 {
+		return max(rows, cols)
+	}
+
+	// Minimize space complexity. O(min(str1, str2) instead of O(str1)
+	if cols > rows {
+		rows, cols = cols, rows
+		str1, str2 = str2, str1
+	}
+
+	dp := make([]uint16, cols+increment)
+
+	for i := 0; i <= rows; i++ {
+		left := uint16(i)
+
+		for j := 1; j <= cols; j++ {
+			if i == 0 {
+				dp[j], left = uint16(j), dp[j]
+			} else {
+				diag, top := dp[j-1], dp[j]
+
+				if !isSameChar(str2[i-1], str1[j-1], caseSensitive) {
+					diag = min(left, min(diag, top)) + uint16(increment)
+				}
+
+				dp[j-1], left = left, diag
+			}
+		}
+
+		dp[cols] = left
+	}
+
+	return int(dp[cols])
+}
+
+func isSameChar(c1, c2 rune, caseSensitive bool) bool {
+	if c1 == c2 {
+		return true
+	}
+
+	if caseSensitive {
+		return false
+	}
+
+	return c1 == c2-32 || c1-32 == c2
+}
+
+func min(a, b uint16) uint16 {
+	if a <= b {
+		return a
+	}
+
+	return b
+}
+
+func max(a, b int) int {
+	if a >= b {
+		return a
+	}
+
+	return b
+}

test/levenshtein_test.go

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+package test_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/rohitsubedi/levenshtein"
+)
+
+func TestMinOperationToConvertOneStringToAnother1(t *testing.T) {
+	destString := "DE-2341-00001"
+	// For same strings
+	minOperation := levenshtein.GetLevenshteinDistance([]rune(destString), []rune(destString), false)
+	assert.Equal(t, 0, minOperation)
+	// For same strings but different case(lower case)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune(strings.ToLower(destString)), []rune(destString), false)
+	assert.Equal(t, 0, minOperation)
+	// For string with 1 char missing
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("D-2341-00001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-231-00001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-2341-0001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-234100001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	// For string with 1 extra char
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DEE-2341-00001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-23441-00001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-2341-000001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-2341--00001"), []rune(destString), false)
+	assert.Equal(t, 1, minOperation)
+	// For string with 2 char missing
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("-2341-00001"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-21-00001"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-2341-000"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE234100001"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+}
+
+func TestMinOperationToConvertOneStringToAnother2(t *testing.T) {
+	destString := "DE-2341-00001"
+	// For string with 2 extra char
+	minOperation := levenshtein.GetLevenshteinDistance([]rune("DEE--2341-00001"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-2344-1-00001"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-2341-0000199"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE--2341--00001"), []rune(destString), false)
+	assert.Equal(t, 2, minOperation)
+	// For string with more than 2 char missing
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("2341-00001"), []rune(destString), false)
+	assert.Equal(t, 3, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE-34-001"), []rune(destString), false)
+	assert.Equal(t, 4, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DE34-001"), []rune(destString), false)
+	assert.Equal(t, 5, minOperation)
+	// For string with more than 2 extra char
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DEE--23341-00001"), []rune(destString), false)
+	assert.Equal(t, 3, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DEE--23341-000001"), []rune(destString), false)
+	assert.Equal(t, 4, minOperation)
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("DEE--233414-000001"), []rune(destString), false)
+	assert.Equal(t, 5, minOperation)
+	// Test case sensitive
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("ROHIT"), []rune("rohit"), true)
+	assert.Equal(t, 5, minOperation)
+	// Test case in sensitive
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("ROHIT"), []rune("rohit"), false)
+	assert.Equal(t, 0, minOperation)
+	// UTF-8 characters
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("rohit"), []rune("röhit"), false)
+	assert.Equal(t, 1, minOperation)
+	// Test empty string
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("ROHIT"), []rune(""), true)
+	assert.Equal(t, 5, minOperation)
+	// Test empty string
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("ö"), []rune(""), true)
+	assert.Equal(t, 1, minOperation)
+	// Test case in sensitive
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("ROHIT"), []rune("tihor"), false)
+	assert.Equal(t, 4, minOperation)
+	// UTF-8 characters same
+	minOperation = levenshtein.GetLevenshteinDistance([]rune("röhit"), []rune("röhit"), false)
+	assert.Equal(t, 0, minOperation)
+}