Commit b633a48

authored

Merge pull request #18 from mihirs16/master

2 parents 0688d0e + 7bb22e8 commit b633a48Copy full SHA for b633a48

File tree

+125

-0

lines changed

+125

-0

lines changed

Lines changed: 38 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,38 @@`
	`1`	`+# add two numbers \| leetcode 02 \| https://leetcode.com/problems/add-two-numbers/`
	`2`	`+`
	`3`	`+# Definition for singly-linked list.`
	`4`	`+class ListNode:`
	`5`	`+ def __init__(self, val=0, next=None):`
	`6`	`+ self.val = val`
	`7`	`+ self.next = next`
	`8`	`+`
	`9`	`+class Solution:`
	`10`	`+ def addTwoNumbers(self, l1: list[ListNode], l2: list[ListNode]) -> list[ListNode]:`
	`11`	`+ res = ListNode()`
	`12`	`+ head = res`
	`13`	`+`
	`14`	`+ while l1 != None or l2 != None:`
	`15`	`+ if l1 == None:`
	`16`	`+ this_val = res.val + l2.val`
	`17`	`+ l2 = l2.next`
	`18`	`+ elif l2 == None:`
	`19`	`+ this_val = res.val + l1.val`
	`20`	`+ l1 = l1.next`
	`21`	`+ else:`
	`22`	`+ this_val = res.val + l1.val + l2.val`
	`23`	`+ l1, l2 = l1.next, l2.next`
	`24`	`+`
	`25`	`+ this_digit = this_val % 10`
	`26`	`+ next_digit = this_val // 10`
	`27`	`+`
	`28`	`+ res.val = this_digit`
	`29`	`+ if l1 != None or l2 != None:`
	`30`	`+ res.next = ListNode(next_digit)`
	`31`	`+ res = res.next`
	`32`	`+`
	`33`	`+ if next_digit > 0:`
	`34`	`+ res.next = ListNode(next_digit)`
	`35`	`+ res = res.next`
	`36`	`+`
	`37`	`+ return head`
	`38`	`+`

Lines changed: 18 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,18 @@`
	`1`	`+# longest substring without repeating characters \| leetcode 03 \| https://leetcode.com/problems/longest-substring-without-repeating-characters`
	`2`	`+# sliding window; remove elements until last occurence of current duplicate`
	`3`	`+`
	`4`	`+class Solution:`
	`5`	`+ def lengthOfLongestSubstring(self, s: str) -> int:`
	`6`	`+ ptrL = 0`
	`7`	`+ seen = dict()`
	`8`	`+ longest = 0`
	`9`	`+`
	`10`	`+ for ptrR in range(len(s)):`
	`11`	`+ while seen.get(s[ptrR]) is not None:`
	`12`	`+ seen.pop(s[ptrL])`
	`13`	`+ ptrL += 1`
	`14`	`+ seen[s[ptrR]] = True`
	`15`	`+ longest = max(ptrR - ptrL + 1, longest)`
	`16`	`+`
	`17`	`+ return longest`
	`18`	`+`

Lines changed: 22 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,22 @@`
	`1`	`+# longest consecutive sequence \| leetcode 128 \| https://leetcode.com/problems/longest-consecutive-sequence/`
	`2`	`+# set to look-up previous and next numbers; nested while loop is O(2n)`
	`3`	`+`
	`4`	`+class Solution:`
	`5`	`+ def longestConsecutive(self, nums: list[int]) -> int:`
	`6`	`+ if nums == []:`
	`7`	`+ return 0`
	`8`	`+`
	`9`	`+ all = set(nums)`
	`10`	`+ longest = 0`
	`11`	`+`
	`12`	`+ for each in all:`
	`13`	`+ if each - 1 not in all:`
	`14`	`+ curr = each`
	`15`	`+ seq = 1`
	`16`	`+ while curr + 1 in all:`
	`17`	`+ seq += 1`
	`18`	`+ curr = curr + 1`
	`19`	`+ if seq > longest:`
	`20`	`+ longest = seq`
	`21`	`+`
	`22`	`+ return longest`

Lines changed: 23 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,23 @@`
	`1`	`+# longest repeating character replacement \| leetcode 424 \| https://leetcode.com/problems/longest-repeating-character-replacement/`
	`2`	`+# keep track of max freq in sliding window and check if size of window - max freq > k`
	`3`	`+`
	`4`	`+class Solution:`
	`5`	`+ def characterReplacement(self, s: str, k: int) -> int:`
	`6`	`+ ptrL = 0`
	`7`	`+ ptrR = 0`
	`8`	`+ longest = 0`
	`9`	`+ freq = dict()`
	`10`	`+ max_freq = 0`
	`11`	`+ w_size = 0`
	`12`	`+`
	`13`	`+ for ptrR in range(len(s)):`
	`14`	`+ freq[s[ptrR]] = 1 + freq.get(s[ptrR], 0)`
	`15`	`+ max_freq = max(max_freq, freq[s[ptrR]])`
	`16`	`+`
	`17`	`+ if (ptrR - ptrL + 1) - max_freq > k:`
	`18`	`+ freq[s[ptrL]] -= 1`
	`19`	`+ ptrL += 1`
	`20`	`+`
	`21`	`+ longest = max(longest, (ptrR - ptrL + 1))`
	`22`	`+`
	`23`	`+ return longest`

Lines changed: 24 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,24 @@`
	`1`	`+# find all anagrams in string \| leetcode 438 \| https://leetcode.com/problems/find-all-anagrams-in-a-string/`
	`2`	`+# sliding window to track "which" substring; add ptr2 to counter, remove ptr1 from counter`
	`3`	`+`
	`4`	`+`
	`5`	`+from collections import Counter`
	`6`	`+`
	`7`	`+class Solution:`
	`8`	`+ def findAnagrams(self, s: str, p: str) -> list[int]:`
	`9`	`+ Ns, Np = len(s), len(p)`
	`10`	`+ ptr1 = 0`
	`11`	`+ ptr2 = Np - 1`
	`12`	`+ anagrams = []`
	`13`	`+ freq_s, freq_p = Counter(s[ptr1:(ptr2 + 1)]), Counter(p)`
	`14`	`+`
	`15`	`+ while ptr2 < Ns:`
	`16`	`+ if freq_s == freq_p:`
	`17`	`+ anagrams.append(ptr1)`
	`18`	`+ freq_s[s[ptr1]] -= 1`
	`19`	`+ ptr1 += 1`
	`20`	`+ ptr2 += 1`
	`21`	`+ if ptr2 != Ns:`
	`22`	`+ freq_s[s[ptr2]] = 1 + freq_s.get(s[ptr2], 0)`
	`23`	`+`
	`24`	`+ return anagrams`

Comments

(0)