Python 刷Leetcode题库，顺带学英语单词（14）

N-Queens

The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.    [#51]

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 '.' both indicate a queen and an empty space respectively.

Example:
Input: 4
Output: [
[".Q..", // Solution 1
"...Q",
"Q...",
"..Q."],
["..Q.", // Solution 2
"Q...",
"...Q",
".Q.."]
]
Explanation: There exist two distinct solutions to the 4-queens puzzle as shown above.

N-Queens II

The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.    [#52]

Given an integer n, return the number of distinct solutions to the n-queens puzzle.

   Example:

Input: 4
    Output: 2
    Explanation: There are two distinct solutions to the 4-queens puzzle as shown
    below.
    [
    [".Q..", // Solution 1
    "...Q",
    "Q...",
    "..Q."],
    ["..Q.", // Solution 2
    "Q...",
    "...Q",
    ".Q.."]
    ]