Description
Binary trees can sometimes be very difficult to work with. Fortunately, there is a class of trees with some really nice properties. A rooted binary tree is called “nice”, if every node is either a leaf, or has exactly two children.
For example, the following tree is nice,
but the following tree is not.
The leaves of a nice binary tree are labeled by the letter ‘l’, and other nodes are labeled by the letter ‘n’.
Given the pre-order traversal of a nice binary tree, you are required to find the depth of the tree.
Notes :
1. The depth of a tree is defined as the length of the longest path with one end at the root.
2. The pre-order traversal of the tree in the first image above produces the string “nlnnlll”.
Input
The first line contains the number of test cases T. T lines follow. Each line contains a string, which represents the pre-order traversal of a “nice” binary tree. Leaves are represented by the letter ‘l’ and other nodes by the letter ‘n’. The input is guaranteed to be the preorder traversal of a nice binary tree.
0 < T < 20
Length of the input string in each test case is at most 10000.
Output
Output one line for each test case, containing a single integer, the depth of tree.
Sample Input
3
l
nlnll
nlnnlll
Sample Output
0
2
3
#include<bits/stdc++.h>
using namespace std;
const int maxn = 10005;
char str[maxn];
int pos,height;
void dfs(int depth){
pos++;
height = max(depth,height);
if (str[pos] == ' ') return;
if (str[pos] == 'l') return;
if (str[pos] == 'n'){
dfs(depth + 1); //left
dfs(depth + 1); //right;
}
}
int main(){
int T;
scanf("%d",&T);
while (T--){
memset(str,0,sizeof(str));
height = 0,pos = -1;
scanf("%s",str);
dfs(0);
cout << height << endl;
}
return 0;
}