Merge pull request algorithm004-01#380 from weapon008/master

melody-li · web-flow · commit 7934fbaa1675 · 2019-10-28T12:05:29.000+08:00
451-Week 02
diff --git a/Week 02/id_451/LeetCode_144_451.go b/Week 02/id_451/LeetCode_144_451.go
@@ -0,0 +1,47 @@
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+type Stack struct {
+	list *list.List
+}
+
+func NewStack() *Stack {
+	list := list.New()
+	return &Stack{list}
+}
+
+func (stack *Stack) Push(value interface{}) {
+	stack.list.PushBack(value)
+}
+
+func (stack *Stack) Pop() interface{} {
+	e := stack.list.Back()
+	if e != nil {
+		stack.list.Remove(e)
+		return e.Value
+	}
+	return nil
+}
+func (stack *Stack) Len() int {
+	return stack.list.Len()
+}
+func preorderTraversal(root *TreeNode) (res []int) {
+	s := NewStack()
+	t := root
+	for t != nil || s.Len() > 0 {
+		if t == nil {
+			t = s.Pop().(*TreeNode)
+			t = t.Right
+			continue
+		}
+		res = append(res, t.Val)
+		s.Push(t)
+		t = t.Left
+	}
+	return
+}
diff --git a/Week 02/id_451/LeetCode_49_451.go b/Week 02/id_451/LeetCode_49_451.go
@@ -0,0 +1,32 @@
+
+type hash map[rune]int
+
+func NewHash() hash {
+	hmap := make(hash)
+	return hmap
+}
+
+func (hm hash) hash(s string) (hs string) {
+	for _, a := range s {
+		hm[a] += 1
+	}
+	for i := 0; i < 26; i++ {
+		a := rune(97 + i)
+		hs += fmt.Sprintf(`%s:%d,`, a, hm[a])
+	}
+	return hs
+}
+
+func groupAnagrams(strs []string) (lres [][]string) {
+	res := make(map[string][]string)
+	for _, s := range strs {
+		hmap := NewHash()
+		h := hmap.hash(s)
+		res[h] = append(res[h], s)
+	}
+
+	for _, s := range res {
+		lres = append(lres, s)
+	}
+	return
+}
diff --git a/Week 02/id_451/LeetCode_94_451.go b/Week 02/id_451/LeetCode_94_451.go
@@ -0,0 +1,40 @@
+type Stack struct {
+	list *list.List
+}
+
+func NewStack() *Stack {
+	list := list.New()
+	return &Stack{list}
+}
+
+func (stack *Stack) Push(value interface{}) {
+	stack.list.PushBack(value)
+}
+
+func (stack *Stack) Pop() interface{} {
+	e := stack.list.Back()
+	if e != nil {
+		stack.list.Remove(e)
+		return e.Value
+	}
+	return nil
+}
+func (stack *Stack) Len() int {
+	return stack.list.Len()
+}
+
+func inorderTraversal(root *TreeNode) (res []int) {
+	s := NewStack()
+	t := root
+	for t != nil || s.Len() > 0 {
+		if t == nil {
+			t = s.Pop().(*TreeNode)
+			res = append(res, t.Val)
+			t = t.Right
+			continue
+		}
+		s.Push(t)
+		t = t.Left
+	}
+	return
+}
