Commit 20280c8

committed

--update: replaced indexof with Map(), throw error on missing arguments

1 parent 479e925 commit 20280c8Copy full SHA for 20280c8

File tree

+15

-1

lines changed

+15

-1

lines changed

Lines changed: 15 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -5,6 +5,8 @@`
`5`	`5`	`*/`
`6`	`6`
`7`	`7`	`function caesarCipher(str, num) {`
	`8`	`+ if (!num) throw new Error('Missing argument: num');`
	`9`	`+`
`8`	`10`	`const lowerCaseString = str.toLowerCase();`
`9`	`11`	`const alphabets = 'abcdefghijklmnopqrstuvwxyz'.split('');`
`10`	`12`	`const totalAlphabets = alphabets.length;`
`@@ -13,6 +15,12 @@ function caesarCipher(str, num) {`
`13`	`15`	`// handle large number, like 300 or -300`
`14`	`16`	`num %= totalAlphabets;`
`15`	`17`
	`18`	`+ const alphabetsMap = new Map();`
	`19`	`+`
	`20`	`+ for (const index in alphabets) {`
	`21`	`+ alphabetsMap[alphabets[index]] = index;`
	`22`	`+ }`
	`23`	`+`
`16`	`24`	`for (let index in lowerCaseString) {`
`17`	`25`	`// get the current character`
`18`	`26`	`const currentCharacter = lowerCaseString[index];`
`@@ -24,7 +32,13 @@ function caesarCipher(str, num) {`
`24`	`32`	`}`
`25`	`33`
`26`	`34`	`// determine the new index`
`27`		`- const currentIndex = alphabets.indexOf(currentCharacter);`
	`35`	`+ /**`
	`36`	`+ * const currentIndex = alphabets.indexOf(currentCharacter);`
	`37`	`+ *`
	`38`	`+ * With indexOf complexity will be O(n*26)`
	`39`	`+ * With Map complexity will be O(n).`
	`40`	`+ */`
	`41`	`+ const currentIndex = Number(alphabetsMap[currentCharacter]);`
`28`	`42`	`let newIndex = currentIndex + num;`
`29`	`43`
`30`	`44`	`// if the index passes 25, restart from 0`

Comments

(0)