JavaScriptAlgorithms/Dynamic-Programming/EditDistance.js at master · seba1rx/JavaScriptAlgorithms · GitHub

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Wikipedia -> https://en.wikipedia.org/wiki/Edit_distance

Q. -> Given two strings `word1` and `word2`. You can perform these operations on any of the string to make both strings similar.

- Insert

- Remove

- Replace

Find the minimum operation cost required to make both same. Each operation cost is 1.

Algorithm details ->

time complexity - O(n*m)

space complexity - O(n*m)

const minimumEditDistance = (word1, word2) => {

const n = word1.length

const m = word2.length

const dp = new Array(m + 1).fill(0).map((item) => [])

fill dp matrix with default values -

- first row is filled considering no elements in word2.

- first column filled considering no elements in word1.

for (let i = 0; i < n + 1; i++) {

dp[0][i] = i

}

for (let i = 0; i < m + 1; i++) {

dp[i][0] = i

}

indexing is 1 based for dp matrix as we defined some known values at first row and first column/

for (let i = 1; i < m + 1; i++) {

for (let j = 1; j < n + 1; j++) {

const letter1 = word1[j - 1]

const letter2 = word2[i - 1]

if (letter1 === letter2) {

dp[i][j] = dp[i - 1][j - 1]

} else {

dp[i][j] = Math.min(dp[i - 1][j], dp[i - 1][j - 1], dp[i][j - 1]) + 1

}

return dp[m][n]

}

export { minimumEditDistance }

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