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update 0501.二叉搜索树中的众数: 修改 java，go 代码

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Yuhao Ju
2022-12-04 15:31:13 +08:00
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parent a4d7ed6142
commit c47a82bc9a
1 changed files with 3 additions and 42 deletions
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problems/0501.二叉搜索树中的众数.md
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@ -54,7 +54,7 @@
1. 这个树都遍历了，用map统计频率 1. 这个树都遍历了，用map统计频率
至于用前中后序那种遍历也不重要，因为就是要全遍历一遍，怎么个遍历法都行，层序遍历都没毛病！ 至于用前中后序哪种遍历也不重要，因为就是要全遍历一遍，怎么个遍历法都行，层序遍历都没毛病！
这里采用前序遍历，代码如下： 这里采用前序遍历，代码如下：
@ -354,7 +354,7 @@ public:
```java ```java
class Solution { class Solution {
public int[] findMode(FindModeInBinarySearchTree.TreeNode root) { public int[] findMode(TreeNode root) {
Map<Integer, Integer> map = new HashMap<>(); Map<Integer, Integer> map = new HashMap<>();
List<Integer> list = new ArrayList<>(); List<Integer> list = new ArrayList<>();
if (root == null) return list.stream().mapToInt(Integer::intValue).toArray(); if (root == null) return list.stream().mapToInt(Integer::intValue).toArray();
@ -375,7 +375,7 @@ class Solution {
return list.stream().mapToInt(Integer::intValue).toArray(); return list.stream().mapToInt(Integer::intValue).toArray();
} }
void searchBST(FindModeInBinarySearchTree.TreeNode curr, Map<Integer, Integer> map) { void searchBST(TreeNode curr, Map<Integer, Integer> map) {
if (curr == null) return; if (curr == null) return;
map.put(curr.val, map.getOrDefault(curr.val, 0) + 1); map.put(curr.val, map.getOrDefault(curr.val, 0) + 1);
searchBST(curr.left, map); searchBST(curr.left, map);
@ -556,46 +556,7 @@ class Solution:
``` ```
## Go ## Go
暴力法（非BSL）
```go
func findMode(root *TreeNode) []int {
var history map[int]int
var maxValue int
var maxIndex int
var result []int
history=make(map[int]int)
traversal(root,history)
for k,value:=range history{
if value>maxValue{
maxValue=value
maxIndex=k
}
}
for k,value:=range history{
if value==history[maxIndex]{
result=append(result,k)
}
}
return result
}
func traversal(root *TreeNode,history map[int]int){
if root.Left!=nil{
traversal(root.Left,history)
}
if value,ok:=history[root.Val];ok{
history[root.Val]=value+1
}else{
history[root.Val]=1
}
if root.Right!=nil{
traversal(root.Right,history)
}
}
```
计数法，不使用额外空间，利用二叉树性质，中序遍历 计数法，不使用额外空间，利用二叉树性质，中序遍历
```go ```go
func findMode(root *TreeNode) []int { func findMode(root *TreeNode) []int {
res := make([]int, 0) res := make([]int, 0)