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add golang solution for lcof problem 32
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6 files changed

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6 files changed

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‎lcof/面试题32 - I. 从上到下打印二叉树/README.md

+29
Original file line numberDiff line numberDiff line change
@@ -122,7 +122,36 @@ var levelOrder = function(root) {
122122
};
123123
```
124124

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### Go
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```go
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func levelOrder(root *TreeNode) []int {
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if root == nil {
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return []int{}
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}
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q := []*TreeNode{}
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q = append(q,root)
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//层序遍历,用队列,遍历到谁,就把谁的左右结点加入队列
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res := []int{}
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for len(q) != 0 {
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tmp := q[0]
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q = q[1:]
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res = append(res,tmp.Val)
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if tmp.Left != nil {
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q = append(q,tmp.Left)
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}
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if tmp.Right != nil {
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q = append(q,tmp.Right)
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}
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}
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return res
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}
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```
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125153
### ...
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126155
```
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128157
```

‎lcof/面试题32 - I. 从上到下打印二叉树/Solution.go

+21
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
1+
func levelOrder(root *TreeNode) []int {
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if root == nil {
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return []int{}
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}
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q := []*TreeNode{}
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q = append(q,root)
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//层序遍历,用队列,遍历到谁,就把谁的左右结点加入队列
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res := []int{}
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for len(q) != 0 {
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tmp := q[0]
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q = q[1:]
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res = append(res,tmp.Val)
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if tmp.Left != nil {
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q = append(q,tmp.Left)
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}
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if tmp.Right != nil {
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q = append(q,tmp.Right)
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}
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}
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return res
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}

‎lcof/面试题32 - II. 从上到下打印二叉树 II/README.md

+35
Original file line numberDiff line numberDiff line change
@@ -142,7 +142,42 @@ var levelOrder = function(root) {
142142
};
143143
```
144144

145+
### Go
146+
147+
```go
148+
func levelOrder(root *TreeNode) [][]int {
149+
if root == nil {
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return nil
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}
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res := [][]int{}
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queue := []*TreeNode{}
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queue = append(queue,root)
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for len(queue) != 0 {
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size := len(queue)
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ans := []int{}
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//利用一个变量记录每层大小
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for size > 0 {
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cur := queue[0]
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ans = append(ans, cur.Val)
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queue = queue[1:]
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size--
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if cur.Left != nil {
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queue = append(queue, cur.Left)
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}
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if cur.Right != nil {
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queue = append(queue, cur.Right)
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}
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}
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res = append(res, ans)
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}
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return res
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}
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```
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145179
### ...
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146181
```
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148183
```

‎lcof/面试题32 - II. 从上到下打印二叉树 II/Solution.go

+27
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
1+
func levelOrder(root *TreeNode) [][]int {
2+
if root == nil {
3+
return nil
4+
}
5+
res := [][]int{}
6+
queue := []*TreeNode{}
7+
queue = append(queue,root)
8+
for len(queue) != 0 {
9+
size := len(queue)
10+
ans := []int{}
11+
//利用一个变量记录每层大小
12+
for size > 0 {
13+
cur := queue[0]
14+
ans = append(ans, cur.Val)
15+
queue = queue[1:]
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size--
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if cur.Left != nil {
18+
queue = append(queue, cur.Left)
19+
}
20+
if cur.Right != nil {
21+
queue = append(queue, cur.Right)
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}
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}
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res = append(res, ans)
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}
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return res
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}

‎lcof/面试题32 - III. 从上到下打印二叉树 III/README.md

+42
Original file line numberDiff line numberDiff line change
@@ -157,7 +157,49 @@ var levelOrder = function(root) {
157157
};
158158
```
159159

160+
### Go
161+
162+
```go
163+
func levelOrder(root *TreeNode) [][]int {
164+
if root == nil {
165+
return nil
166+
}
167+
res := [][]int{}
168+
queue := []*TreeNode{}
169+
queue = append(queue,root)
170+
level := 0
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for len(queue) != 0 {
172+
size := len(queue)
173+
ans := []int{}
174+
//size记录每层大小,level记录层数
175+
for size > 0 {
176+
cur := queue[0]
177+
if level & 1 == 0 {
178+
ans = append(ans, cur.Val)
179+
} else {
180+
ans = append([]int{cur.Val},ans...)
181+
}
182+
183+
queue = queue[1:]
184+
size--
185+
if cur.Left != nil {
186+
queue = append(queue, cur.Left)
187+
}
188+
if cur.Right != nil {
189+
queue = append(queue, cur.Right)
190+
}
191+
}
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level++
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res = append(res, ans)
194+
}
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return res
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}
197+
```
198+
199+
200+
160201
### ...
202+
161203
```
162204
163205
```

‎lcof/面试题32 - III. 从上到下打印二叉树 III/Solution.go

+34
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,34 @@
1+
func levelOrder(root *TreeNode) [][]int {
2+
if root == nil {
3+
return nil
4+
}
5+
res := [][]int{}
6+
queue := []*TreeNode{}
7+
queue = append(queue,root)
8+
level := 0
9+
for len(queue) != 0 {
10+
size := len(queue)
11+
ans := []int{}
12+
//size记录每层大小,level记录层数
13+
for size > 0 {
14+
cur := queue[0]
15+
if level & 1 == 0 {
16+
ans = append(ans, cur.Val)
17+
} else {
18+
ans = append([]int{cur.Val},ans...)
19+
}
20+
21+
queue = queue[1:]
22+
size--
23+
if cur.Left != nil {
24+
queue = append(queue, cur.Left)
25+
}
26+
if cur.Right != nil {
27+
queue = append(queue, cur.Right)
28+
}
29+
}
30+
level++
31+
res = append(res, ans)
32+
}
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return res
34+
}

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