Commit b25024c

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Merge pull request #23 from mihirs16/master

added leetcode questions

2 parents 484e08a + 3d57742 commit b25024cCopy full SHA for b25024c

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	`1`	`+# find the index of the first occurrence of a string \| leetcode 28 \| https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/`
	`2`	`+# sliding window to match each character of the haystack with the needle; no slices.`
	`3`	`+`
	`4`	`+class Solution:`
	`5`	`+ def strStr(self, haystack: str, needle: str) -> int:`
	`6`	`+ # ----- using regex -----`
	`7`	`+ # if needle == '':`
	`8`	`+ # return 0`
	`9`	`+`
	`10`	`+ # import re`
	`11`	`+ # match = re.search(needle, haystack)`
	`12`	`+ # return match.start() if match else -1`
	`13`	`+`
	`14`	`+ # ----- using sliding windows -----`
	`15`	`+ ptrL, ptrR = 0, 0`
	`16`	`+ N_needle, N_haystack = len(needle), len(haystack)`
	`17`	`+ while ptrR < N_haystack:`
	`18`	`+ if haystack[ptrR] == needle[ptrR - ptrL]:`
	`19`	`+ ptrR += 1`
	`20`	`+ if ptrR - ptrL > N_needle - 1:`
	`21`	`+ return ptrL`
	`22`	`+ else:`
	`23`	`+ ptrR = ptrL + 1`
	`24`	`+ ptrL += 1`
	`25`	`+`
	`26`	`+ return -1`

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	`1`	`+# string compression \| leetcode 443 \| https://leetcode.com/problems/string-compression/`
	`2`	`+# sliding window to keep track of a char's occurence`
	`3`	`+`
	`4`	`+class Solution:`
	`5`	`+ def compress(self, chars: list[str]) -> int:`
	`6`	`+ ptrL, ptrR = 0, 0`
	`7`	`+ total = 0`
	`8`	`+ chars += " "`
	`9`	`+`
	`10`	`+ while ptrR < len(chars):`
	`11`	`+ if chars[ptrL] != chars[ptrR]:`
	`12`	`+ chars[total] = chars[ptrL]`
	`13`	`+ total += 1`
	`14`	`+ group = ptrR - ptrL`
	`15`	`+ if group > 1:`
	`16`	`+ for x in str(group):`
	`17`	`+ chars[total] = x`
	`18`	`+ total += 1`
	`19`	`+ ptrL = ptrR`
	`20`	`+ ptrR += 1`
	`21`	`+`
	`22`	`+ return total`

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