Several bug fixes and improvements (#945)

* Update Dockerfile for code debugging.

* Format Python code using Black.

* Improve dark theme by defining html classes for the figures, animations and cover images.

* Fix several glossary translation.

* Update a code comment.

* Fix climbing_stairs_backtrack: the pruning should not require the sorted choices list.

* Update the code of array and list traversal.

* Fix a rendering issue of README.md

* Update code of list traversal.

* Fix array_definition.png

* Update README.md

* Fix max_capacity_moving_short_board.png

* Fix array.dart

* Fix array.dart

* Fix array.dart

* Fix array.dart

codes/zig/chapter_array_and_linkedlist/array.zig

@@ -51,12 +51,12 @@ pub fn traverse(nums: []i32) void {
     // 通过索引遍历数组
     var i: i32 = 0;
     while (i < nums.len) : (i += 1) {
-        count += 1;
+        count += nums[i];
     }
     count = 0;
-    // 直接遍历数组
-    for (nums) |_| {
-        count += 1;
+    // 直接遍历数组元素
+    for (nums) |num| {
+        count += num;
     }
 }
 

codes/zig/chapter_array_and_linkedlist/list.zig

@@ -52,13 +52,12 @@ pub fn main() !void {
     var count: i32 = 0;
     var i: i32 = 0;
     while (i < nums.items.len) : (i += 1) {
-        count += 1;
+        count += nums[i];
     }
-
     // 直接遍历列表元素
     count = 0;
-    for (nums.items) |_| {
-        count += 1;
+    for (nums.items) |x| {
+        count += x;
     }
 
     // 拼接两个列表