SPOJ NICEBTRE - Nice Binary Trees（树 先序遍历）

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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

 

+ View Code?

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#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] == '\0')   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; }