Freaks City

The task is to generate all possible combinations of r distinct numbers from the set {1, 2, ..., n}. A combination is an unordered selection, meaning {1, 2, 3} is the same as {3, 2, 1}. We need to print each combination on a new line, with numbers sorted in ascending order and each number occupying exactly three characters of space. The combina ...

Problem Description Given a non-strictly increasing (sorted with possible duplicates) integer aray nums, remove the duplicates in-place succh that each unique element appears only once. Maintain the relative order of the unique elements and return the number of unique elements in nums. Let k be the count of unique elements. To pass the test cas ...

The three-sum problem requires finding all unique triplets in an array that add up to zero. While depth-first search can solve this after sorting, a more efficient approach uses the two-pointer technique on a sorted array. Key Points Use two pointers, not a single pointer—common mistake to avoid Recommended solving time: 20 minutes Problem De ...

Swapping Adjacent Nodes in Pairs Manipulating node connections uniformly requires a sentinel (dummy) node to eliminate edge cases for the head element. To exchange adjacent pairs, position a reference pointer immediately before the pair undergoing modification. The iterative approach tracks three critical references: the node preceding the pair ...

The Hungarian Algorithm is a classic approach to solve the Maximum Bipartite Matching problem. In a bipartite graph, it identifies the largest set of edges such that each vertex is connected to at most one adjacent vertex. To illustrate its operation, consider a bipartite graph with left vertices (tasks: A, B, C, D) and right vetrices (workers: ...

Accumulate Function The accumulate function performs operations on a sequence: accumulate(first, last, val, op); Where first/last are iterators, val is the initial value, and op is the operation (addition, subtraction, etc.). Example Usage #include <numeric> #include <iostream> #include <vector> using namespace std; int main ...

It is clear that S represents the initial magic value, k is the number of selected items, and x is given in the problem. Noting that x is large but k and n are small, we can define a state that tracks the i-th item, the number of selected items j, and the sum modulo k as l. The goal is to maximize the initial magic value, as higher values reduc ...

Maximum Depth of a Binary Tree Given a binary tree, determine its maximum depth - the number of nodes along the longest path from the root node to the farthest leaf node. Recursive Approach Using postorder traversal (left-right-root) to calculate node height: struct TreeNode { int val; TreeNode* left; TreeNode* right; TreeNode(i ...

House Robber I The classic house robber problem involves selecting houses to rob such that adjacent houses cannot both be robbed, maximizing total profit. For each house, there are two choices: rob it or skip it. The decision at each position aims to maximize accumulated wealth. State Defniition: wealth[i] represents the maximum money obtainabl ...

Problem B: What, More Kangaroos? Operations 1 and 2 nullify eachother, as do operations 3 and 4. The problem reduces to applying positive integer operations on two buttons only, yielding four enumeration cases. With operations 1 and 3 chosen, let operation 1 execute x times and operation 3 execute y times (x, y > 0). The goal is maximizing i ...