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Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.
An example is the root-to-leaf path 1->2->3 which represents the number 123.
Find the total sum of all root-to-leaf numbers.
For example,
1 / 2 3
The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.
Return the sum = 12 + 13 = 25.
Tree Depth-first Search
这道题采用基于DFS的递归来做。
#include<iostream>
using namespace std;
struct TreeNode
{
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
void digui(TreeNode* root,int len,int &result)
{
if(root->left==NULL&&root->right==NULL)
{
result=result+len;
return;
}
if(root->left!=NULL)
{
digui(root->left,len*10+root->left->val,result);
}
if(root->right!=NULL)
{
digui(root->right,len*10+root->right->val,result);
}
return;
}
int sumNumbers(TreeNode* root){
int last=0;
if(root==NULL)
return 0;
digui(root,root->val,last);
return last;
}
int main()
{
TreeNode* root=new TreeNode(0);
root->left=new TreeNode(1);
root->right=new TreeNode(3);
cout<<sumNumbers(root)<<endl;
}
leetcode_129题——Sum Root to Leaf Numbers（基于DFS的递归）
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原文地址：http://www.cnblogs.com/yanliang12138/p/4554111.html
