Algorithm
本周选择的算法题是：N-Queens II。
规则
The n-queens puzzle is the problem of placing n queens on an n x n chessboard such that no two queens attack each other.
Given an integer n, return the number of distinct solutions to the n-queens puzzle.
Example 1:
Input: n = 4
Output: 2
Explanation: There are two distinct solutions to the 4-queens puzzle as shown.
Example 2:
Input: n = 1
Output: 1
Constraints:
1 <= n <= 9
Solution
class Solution:
def totalNQueens(self, n: int) -> int:
if n == 0: return 0
def dfs(matrix, diagonal_left, diagonal_right):
i = len(matrix)
if i == n:
self.ans += 1
return
for j in range(n):
if j not in matrix and (j - i) not in diagonal_left and (j + i) not in diagonal_right:
dfs(matrix + [j], diagonal_left + [j-i], diagonal_right + [j+i])
self.ans = 0
for j in range(n):
dfs([j], [j], [j])
return self.ans
Review
This post will make you rethink which programming languages are worth learning
还是不能忽视行业的重要性。Java、C 就不说了，JavaScript、HTML/CSS 之所以很流行，是因为 web 开发者在劳动市场上很受欢迎；Python 和 SQL 也很流行，这和数据科学、数据分析、数据工程师有关。
但语言与工作满意度是无关的。
要选择语言，还是要思考自己喜欢做什么，构建 API，还是做有挑战性的交互页面，又或是支撑系统优化的数据分析，不同岗位角色决定了不同的适用语言。
Tip
用油猴脚本完全重写了 Chrome 插件，在内部小团队里内测中，可以解决 Chrome 插件（unpacked）不能自动更新的问题。