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摘要： The n-queens puzzle is the problem of placing n queens on an n*n chessboard such that no two queens attack each other. Given an integer n, return all distinct solutions to the n-queens puzzle. Each solution contains a distinct board configuration of the n-queens' placement, where 'Q' and 阅读全文

摘要： The n-queens puzzle is the problem of placing n queens on an n*n chessboard such that no two queens attack each other. Given an integer n, return all distinct solutions to the n-queens puzzle. Each solution contains a distinct board configuration of the n-queens' placement, where 'Q' and 阅读全文

摘要： Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string. If the last word does not exist, return 0. Note: A word is defined as a character sequence consists of non-space characters only. For example, Given s = " 阅读全文

摘要： Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Note: A solution using O(n) space is pretty straight forward. Could you devise a constant space solution? Solution: 1. recursive solution. O(n) space. get inorder list first. ... 阅读全文

摘要： Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. Solution: Dynamic Programming. Space O(N). 1 class Solution { 2 public: 3 int ... 阅读全文