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Complete "longest common ..." examples (#100)

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* no else return

* fix var ref

* fix importing/requiring dependencies

* complete longest common examples
This commit is contained in:
Max Beatty
2019-03-28 14:52:55 -07:00
committed by Aditya Bhargava
parent c23ca90b83
commit 5b675cc2e8
22 changed files with 235 additions and 125 deletions
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59
09_dynamic_programming/ES6/01_longest_common_subsequence.js
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@@ -1,7 +1,54 @@
if (word_a[i] === word_b[j]) {
// The letters match
cell[i][j] = cell[i - 1][j - 1] + 1;
} else {
// The letters don't match
cell[i][j] = Math.max(cell[i - 1][j], cell[i][j - 1]);
function createMatrix(rows, cols) {
const matrix = new Array(rows);
for (let i = 0; i < matrix.length; i++) {
matrix[i] = new Array(cols).fill(0);
}
return matrix;
}
function substring(a, b) {
const cell = createMatrix(a.length + 1, b.length + 1);
let lcs = 0;
let lastSubIndex = 0;
for (let i = 1; i <= a.length; i++) {
for (let j = 1; j <= b.length; j++) {
if (a[i - 1] === b[j - 1]) {
cell[i][j] = cell[i - 1][j - 1] + 1;
if (cell[i][j] > lcs) {
lcs = cell[i][j];
lastSubIndex = i;
}
} else {
cell[i][j] = 0;
}
}
}
return a.slice(lastSubIndex - lcs, lastSubIndex);
}
substring("vista", "hish"); // "is"
substring("fish", "hish"); // "ish"
function subsequence(a, b) {
const cell = createMatrix(a.length + 1, b.length + 1);
for (let i = 1; i <= a.length; i++) {
for (let j = 1; j <= b.length; j++) {
if (a[i] === b[j]) {
cell[i][j] = cell[i - 1][j - 1] + 1;
} else {
cell[i][j] = Math.max(cell[i - 1][j], cell[i][j - 1]);
}
}
}
return cell[a.length][b.length];
}
subsequence("fish", "fosh"); // 3
subsequence("fort", "fosh"); // 2

4
09_dynamic_programming/ES6/examples/base.js
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@@ -1,9 +1,7 @@
const initializeMatrix = (rows, cols) => {
export const initializeMatrix = (rows, cols) => {
const matrix = [];
for (let i = 0; i < rows.length; i += 1) {
matrix.push(Array(cols.length).fill(0));
}
return matrix;
};
export default initializeMatrix;

6
09_dynamic_programming/ES6/examples/diff_two_words.js
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@@ -1,8 +1,8 @@
import base from './base';
import { initializeMatrix } from "./base";
const diff = (firstWord, secondWord) => {
const arr1 = firstWord.split('');
const arr2 = secondWord.split('');
const arr1 = firstWord.split("");
const arr2 = secondWord.split("");
const matrix = initializeMatrix(arr1, arr2);
for (let i = 0; i < arr1.length; i += 1) {
for (let j = 0; j < arr2.length; j += 1) {

56
09_dynamic_programming/golang/01_longest_common_subsequence.go
View File

@@ -1,11 +1,53 @@
package main
import "fmt"
func main() {
if word_a[i] == word_b[j] {
cell[i][j] = cell[i-1][j-1] + 1
} else {
cell[i][j] = max(cell[i-1][j], cell[i][j-1])
func createMatrix(rows, cols int) [][]int {
cell := make([][]int, rows)
for i := range cell {
cell[i] = make([]int, cols)
}
return cell
}
func substring(a, b string) string {
lcs := 0
lastSubIndex := 0
cell := createMatrix(len(a)+1, len(b)+1)
for i := 1; i <= len(a); i++ {
for j := 1; j <= len(b); j++ {
if a[i-1] == b[j-1] {
cell[i][j] = cell[i-1][j-1] + 1
if cell[i][j] > lcs {
lcs = cell[i][j]
lastSubIndex = i
}
} else {
cell[i][j] = 0
}
}
}
return a[lastSubIndex-lcs : lastSubIndex]
}
func subsequence(a, b string) int {
cell := createMatrix(len(a)+1, len(b)+1)
for i := 1; i <= len(a); i++ {
for j := 1; j <= len(b); j++ {
if a[i-1] == b[j-1] {
cell[i][j] = cell[i-1][j-1] + 1
} else {
cell[i][j] = cell[i-1][j]
if cell[i][j] < cell[i][j-1] {
cell[i][j] = cell[i][j-1]
}
}
}
}
return cell[len(a)][len(b)]
}

42
09_dynamic_programming/golang/01_longest_common_subsequence_test.go Normal file
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@@ -0,0 +1,42 @@
package main
import "testing"
func TestSubstring(t *testing.T) {
var stests = []struct {
name, a, b, expected string
}{
{"hish-vista", "vista", "hish", "is"},
{"hish-fish", "fish", "hish", "ish"},
}
for _, tt := range stests {
t.Run(tt.name, func(t *testing.T) {
actual := substring(tt.a, tt.b)
if actual != tt.expected {
t.Errorf("Expected %s but received %s", tt.expected, actual)
}
})
}
}
func TestSubsequence(t *testing.T) {
var stests = []struct {
name, a, b string
expected int
}{
{"fosh-fish", "fish", "fosh", 3},
{"fosh-fort", "fort", "fosh", 2},
}
for _, tt := range stests {
t.Run(tt.name, func(t *testing.T) {
actual := subsequence(tt.a, tt.b)
if actual != tt.expected {
t.Errorf("Expected %d but received %d", tt.expected, actual)
}
})
}
}

14
09_dynamic_programming/javascript/examples/base.js
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@@ -1,7 +1,7 @@
export default function initialize_matrix(rows, cols){
let matrix = [];
for (let i = 0; i < rows.length; i++){
matrix.push(Array(cols.length).fill(0));
}
return matrix;
}
module.exports = function initialize_matrix(rows, cols) {
let matrix = [];
for (let i = 0; i < rows.length; i++) {
matrix.push(Array(cols.length).fill(0));
}
return matrix;
};

44
09_dynamic_programming/javascript/examples/diff_two_words.js
View File

@@ -1,25 +1,25 @@
import initialize_matrix as base from "./base.js";
const initialize_matrix = require("./base.js");
export default function diff( firstWord, secondWord ){
let arr1 = firstWord.split('');
let arr2 = secondWord.split('');
let matrix = initialize_matrix(arr1, arr2);
for (let i = 0; i < arr1.length; i++){
for (let j = 0; j < arr2.length; j++){
if( arr1[i] == arr2[j] ){
if( i > 0 && j > 0){
matrix[i][j] = matrix[i - 1][j - 1] + 1;
}else{
matrix[i][j] = 1;
}
} else {
if( i > 0 && j > 0){
matrix[i][j] = Math.max(matrix[i - 1][j], matrix[i][j - 1]);
}else{
matrix[i][j] = 0;
}
}
function diff(firstWord, secondWord) {
let arr1 = firstWord.split("");
let arr2 = secondWord.split("");
let matrix = initialize_matrix(arr1, arr2);
for (let i = 0; i < arr1.length; i++) {
for (let j = 0; j < arr2.length; j++) {
if (arr1[i] == arr2[j]) {
if (i > 0 && j > 0) {
matrix[i][j] = matrix[i - 1][j - 1] + 1;
} else {
matrix[i][j] = 1;
}
} else {
if (i > 0 && j > 0) {
matrix[i][j] = Math.max(matrix[i - 1][j], matrix[i][j - 1]);
} else {
matrix[i][j] = 0;
}
}
}
return matrix[arr1.length-1][arr2.length-1];
}
}
return matrix[arr1.length - 1][arr2.length - 1];
}