NeetCode Analysis - Google Sheets

	A	B	C	D
1	Problem	Level	Solution	Remarks

2	Contains Duplicate - LeetCode	Easy	arrays_and_hashing/contains-duplicate.rb	Returning false if during frequency map calculation sees frequency > 1
3	Valid Anagram - LeetCode	Easy	arrays_and_hashing/valid-anagram.rb	Check if frequency map is same
4	Two Sum - LeetCode	Easy	arrays_and_hashing/two-sum.rb	Store complementary value in hashmap
5	Group Anagrams - LeetCode	Medium	arrays_and_hashing/group-anagrams.rb	Store in hashmap array with sorted word as key
6	Top K Frequent Elements - LeetCode	Medium	arrays_and_hashing/top-k-frequent-elements.rb	Sort frequency map and first k entries
7	Product of Array Except Self - LeetCode	Medium	arrays_and_hashing/product-of-array-except-self.rb	Progressively compute product from both ends and store in two arrays
8	Valid Sudoku - LeetCode	Medium	arrays_and_hashing/valid-sudoku.rb	Use transpose to verify colums, iterate matrix in steps of 3 to capture blocks
9	659 · Encode and Decode Strings - LintCode	Medium	arrays_and_hashing/encode_decode_strings.rb	Convert characters to ascii and delimit them with any symbol in string form
10	Longest Consecutive Sequence - LeetCode	Medium	arrays_and_hashing/longest-consecutive-sequence.rb	In sorted array move cursor to find blocks
11	Valid Palindrome - LeetCode	Easy	two_pointers/valid-palindrome.rb	Downcase and replace other characters using regex
12	Two Sum II - Input Array Is Sorted - LeetCode	Medium	two_pointers/two-sum-ii-input-array-is-so	Two pointers collapsing from ends
13	3Sum - LeetCode	Medium	two_pointers/3sum.rb	In sorted array find complementary two sums, skip same numbers in all pointers
14	Container With Most Water - LeetCode	Medium	two_pointers/container-with-most-water.rb	Min hieght times distance between pointers collapsing from both ends
15	Trapping Rain Water - LeetCode	Hard	two_pointers/trapping-rain-water.rb	Create two arrays of max heights on left and right for each bar. Area possible on each bar is min(l, r) - height[i]
16	Valid Parentheses - LeetCode	Easy	stack/valid-parentheses.rb	Push opening brackets to stack. Pop complementary bracket from stack top, otherwise return false.
17	Min Stack - LeetCode	Medium	stack/min-stack.rb	Keep one extra stack to store min value till that element
18	Evaluate Reverse Polish Notation - LeetCode	Medium	stack/evaluate-reverse-polish-notation.rb	Push numbers to stack and pop a pair when operator is found, push the result back
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