~/lc-grind

Master the art of creating a perfect deep copy of a special linked list where each node contains both next and random pointers, ensuring no connections to the original list remain.

Add two numbers represented as reverse-digit linked lists, handling carries with ease, and return the result as a new linked list.

Master the art of evaluating complex arithmetic expressions with parentheses and unary minus by implementing a stack-based solution that respects operator precedence without using eval().

Efficiently evaluate postfix expressions using a stack to handle operators and operands, simplifying complex arithmetic by processing tokens in reverse polish notation.

Design a stack that supports push, pop, top, and retrieving the minimum element—all in constant O(1) time.

Use a stack to process directory tokens, resolving parent ".." and ignoring current "." directories, to build the cleanest possible absolute path.

Shoot the fewest arrows vertically to burst all balloons by strategically targeting overlapping intervals, a classic greedy approach solved by sorting and scanning.

Transform a sorted array of unique integers into the smallest set of contiguous ranges, representing consecutive numbers as "a->b" and single numbers as "a".

Check if an array contains two nearby duplicates, where the distance between their indices is at most k.

Discover if repeatedly summing the squares of a number's digits leads to eternal happiness (1) or an endless cycle of despair.