Review Swift codes (#1150)

* feat(swift): review for chapter_computational_complexity

* feat(swift): review for chapter_data_structure

* feat(swift): review for chapter_array_and_linkedlist

* feat(swift): review for chapter_stack_and_queue

* feat(swift): review for chapter_hashing

* feat(swift): review for chapter_tree

* feat(swift): add codes for heap article

* feat(swift): review for chapter_heap

* feat(swift): review for chapter_graph

* feat(swift): review for chapter_searching

* feat(swift): review for chapter_sorting

* feat(swift): review for chapter_divide_and_conquer

* feat(swift): review for chapter_backtracking

* feat(swift): review for chapter_dynamic_programming

* feat(swift): review for chapter_greedy

* feat(swift): review for utils

* feat(swift): update ci tool

* feat(swift): trailing closure

* feat(swift): array init

* feat(swift): map index

codes/swift/chapter_greedy/fractional_knapsack.swift

@@ -20,7 +20,7 @@ func fractionalKnapsack(wgt: [Int], val: [Int], cap: Int) -> Double {
     // 创建物品列表，包含两个属性：重量、价值
     var items = zip(wgt, val).map { Item(w: $0, v: $1) }
     // 按照单位价值 item.v / item.w 从高到低进行排序
-    items.sort(by: { -(Double($0.v) / Double($0.w)) < -(Double($1.v) / Double($1.w)) })
+    items.sort { -(Double($0.v) / Double($0.w)) < -(Double($1.v) / Double($1.w)) }
     // 循环贪心选择
     var res = 0.0
     var cap = cap

codes/swift/chapter_greedy/max_capacity.swift

@@ -7,7 +7,7 @@
 /* 最大容量：贪心 */
 func maxCapacity(ht: [Int]) -> Int {
     // 初始化 i, j，使其分列数组两端
-    var i = 0, j = ht.count - 1
+    var i = ht.startIndex, j = ht.endIndex - 1
     // 初始最大容量为 0
     var res = 0
     // 循环贪心选择，直至两板相遇