根据预排序计算完整二叉树的深度
原文:https://www . geesforgeks . org/calculate-depth-full-二叉树-preorder/
给定二叉树的前序,计算其深度(或高度)【从深度 0 开始】。预订单是由两个可能的字符组成的字符串。
- “l”表示叶子
- “n”表示内部节点
给定的树可以看作是一个完整的二叉树,其中每个节点都有 0 或两个子节点。节点的两个子节点可以是“n”或“l ”,也可以是两者的混合。 例:
Input : nlnll
Output : 2
Explanation :
Input : nlnnlll
Output : 3
二叉树的前序是这样遍历的 同样,我们会得到一串字符(由‘n’和‘l’组成),所以也没有必要实现树。 递归函数为: 1)基本情况:返回 0;当 tree[i] = 'l '或 I>= strlen(tree) 2)find _ depth(tree[i++])//左子树 3)find _ depth(tree[i++])//右子树 其中 I 是字符串树的索引。
C++
// C++ program to find height of full binary tree
// using preorder
#include <bits/stdc++.h>
using namespace std;
// function to return max of left subtree height
// or right subtree height
int findDepthRec(char tree[], int n, int& index)
{
if (index >= n || tree[index] == 'l')
return 0;
// calc height of left subtree (In preorder
// left subtree is processed before right)
index++;
int left = findDepthRec(tree, n, index);
// calc height of right subtree
index++;
int right = findDepthRec(tree, n, index);
return max(left, right) + 1;
}
// Wrapper over findDepthRec()
int findDepth(char tree[], int n)
{
int index = 0;
findDepthRec(tree, n, index);
}
// Driver program
int main()
{
// Your C++ Code
char tree[] = "nlnnlll";
int n = strlen(tree);
cout << findDepth(tree, n) << endl;
return 0;
}
Java 语言(一种计算机语言,尤用于创建网站)
// Java program to find height
// of full binary tree using
// preorder
import java .io.*;
class GFG
{
// function to return max
// of left subtree height
// or right subtree height
static int findDepthRec(String tree,
int n, int index)
{
if (index >= n ||
tree.charAt(index) == 'l')
return 0;
// calc height of left subtree
// (In preorder left subtree
// is processed before right)
index++;
int left = findDepthRec(tree,
n, index);
// calc height of
// right subtree
index++;
int right = findDepthRec(tree, n, index);
return Math.max(left, right) + 1;
}
// Wrapper over findDepthRec()
static int findDepth(String tree,
int n)
{
int index = 0;
return (findDepthRec(tree,
n, index));
}
// Driver Code
static public void main(String[] args)
{
String tree = "nlnnlll";
int n = tree.length();
System.out.println(findDepth(tree, n));
}
}
// This code is contributed
// by anuj_67.
Python 3
#Python program to find height of full binary tree
# using preorder
# function to return max of left subtree height
# or right subtree height
def findDepthRec(tree, n, index) :
if (index[0] >= n or tree[index[0]] == 'l'):
return 0
# calc height of left subtree (In preorder
# left subtree is processed before right)
index[0] += 1
left = findDepthRec(tree, n, index)
# calc height of right subtree
index[0] += 1
right = findDepthRec(tree, n, index)
return (max(left, right) + 1)
# Wrapper over findDepthRec()
def findDepth(tree, n) :
index = [0]
return findDepthRec(tree, n, index)
# Driver program to test above functions
if __name__ == '__main__':
tree= "nlnnlll"
n = len(tree)
print(findDepth(tree, n))
# This code is contributed by SHUBHAMSINGH10
C
// C# program to find height of
// full binary tree using preorder
using System;
class GFG {
// function to return max of left subtree
// height or right subtree height
static int findDepthRec(char[] tree, int n, int index)
{
if (index >= n || tree[index] == 'l')
return 0;
// calc height of left subtree (In preorder
// left subtree is processed before right)
index++;
int left = findDepthRec(tree, n, index);
// calc height of right subtree
index++;
int right = findDepthRec(tree, n, index);
return Math.Max(left, right) + 1;
}
// Wrapper over findDepthRec()
static int findDepth(char[] tree, int n)
{
int index = 0;
return (findDepthRec(tree, n, index));
}
// Driver program
static public void Main()
{
char[] tree = "nlnnlll".ToCharArray();
int n = tree.Length;
Console.WriteLine(findDepth(tree, n));
}
}
// This code is contributed by vt_m.
java 描述语言
<script>
// Javascript program to find height of
// full binary tree using preorder
// function to return max of left subtree
// height or right subtree height
function findDepthRec(tree, n, index)
{
if (index >= n || tree[index] == 'l')
return 0;
// calc height of left subtree (In preorder
// left subtree is processed before right)
index++;
let left = findDepthRec(tree, n, index);
// calc height of right subtree
index++;
let right = findDepthRec(tree, n, index);
return Math.max(left, right) + 1;
}
// Wrapper over findDepthRec()
function findDepth(tree, n)
{
let index = 0;
return (findDepthRec(tree, n, index));
}
let tree = "nlnnlll".split('');
let n = tree.length;
document.write(findDepth(tree, n));
</script>
输出:
3
时间复杂度: O(N)
辅助空间: O(1)
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