Freaks City

Given an n × n chessboard, place n queens so that no two attack each other. A valid placement guarantees exactly one queen per row and per column, and at most one queen on every diagonal (both positive and negative slopes). The task is to enumerate every valid configuration, print the first three in lexicographical order, and finally output the ...

Given an array of integers candidates and a target value target, find all unique combinations in candidates where the numbers sum to target. Key constraints: Each number can only be used once in each combination. All numbers (including the target) are positive integers. The result set must not contain duplicate combinations. Examples Example ...

Problem 491: Non-decreasing Subsequences Given an integer array nums, return all the different non-decreasing subsequences that have atleast two elements. The answer can be in any order. When two integers are equal, this counts as a valid increasing sequecne. Example 1: Input: nums = [4,6,7,7] Output: [[4,6],[4,6,7],[4,6,7,7],[4,7],[4,7,7],[6,7 ...

A: Chessboard Rook Placement Given an (n \times n) board where certain positions marked # allow placement, determine the number of ways to place (k) identical, non-attacking rooks. Constraints: (k \leq n \leq 8). Since each row can hold at most one rook, a depth-first search over rows is feasible. The state space is bounded by ((n+1)^n), at mos ...