1582 articles
LC 137 Single Number II extends XOR cancellation to triplets. Learn the ones/twos state machine and the mod-3 bit count, two approaches every FAANG interviewer expects you to derive from scratch.
LeetCode 260 Single Number III: every element appears twice except two unique elements. Master the XOR partition trick used by FAANG interviewers to test deep bitwise reasoning.
LeetCode 191 Number of 1 Bits: count set bits using Brian Kernighan trick n & (n-1). Foundational popcount technique that every FAANG interviewer expects you to know cold.
LeetCode 338 Counting Bits: compute popcount for every integer 0..n in O(n). Master the elegant DP recurrence dp[i] = dp[i >> 1] + (i & 1) that FAANG interviewers love.
LeetCode 190 Reverse Bits: reverse the binary representation of a 32-bit unsigned integer. Master the shift loop and the elegant divide-and-conquer mask reversal used in real-world DSP and crypto code.