feat: Revised the book (#978)

* Sync recent changes to the revised Word.

* Revised the preface chapter

* Revised the introduction chapter

* Revised the computation complexity chapter

* Revised the chapter data structure

* Revised the chapter array and linked list

* Revised the chapter stack and queue

* Revised the chapter hashing

* Revised the chapter tree

* Revised the chapter heap

* Revised the chapter graph

* Revised the chapter searching

* Reivised the sorting chapter

* Revised the divide and conquer chapter

* Revised the chapter backtacking

* Revised the DP chapter

* Revised the greedy chapter

* Revised the appendix chapter

* Revised the preface chapter doubly

* Revised the figures

codes/python/chapter_backtracking/n_queens.py

@@ -24,7 +24,7 @@ def backtrack(
         # 计算该格子对应的主对角线和副对角线
         diag1 = row - col + n - 1
         diag2 = row + col
-        # 剪枝：不允许该格子所在列、主对角线、副对角线存在皇后
+        # 剪枝：不允许该格子所在列、主对角线、副对角线上存在皇后
         if not cols[col] and not diags1[diag1] and not diags2[diag2]:
             # 尝试：将皇后放置在该格子
             state[row][col] = "Q"
@@ -41,8 +41,8 @@ def n_queens(n: int) -> list[list[list[str]]]:
     # 初始化 n*n 大小的棋盘，其中 'Q' 代表皇后，'#' 代表空位
     state = [["#" for _ in range(n)] for _ in range(n)]
     cols = [False] * n  # 记录列是否有皇后
-    diags1 = [False] * (2 * n - 1)  # 记录主对角线是否有皇后
-    diags2 = [False] * (2 * n - 1)  # 记录副对角线是否有皇后
+    diags1 = [False] * (2 * n - 1)  # 记录主对角线上是否有皇后
+    diags2 = [False] * (2 * n - 1)  # 记录副对角线上是否有皇后
     res = []
     backtrack(0, n, state, res, cols, diags1, diags2)