https://oj.leetcode.com/problems/sum-root-to-leaf-numbers/
给一棵树,找从根到叶的路径,并把路径上的数相加,求和。
树的深度优先搜索
/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: int sumNumbers(TreeNode *root) { if(root == NULL) return 0; vector<int> numbers; vector<int> digits; deep(root,numbers,digits); int sum = 0; for(int i = 0; i < numbers.size(); i++) { sum += numbers[i]; } return sum; } void deep(TreeNode *root, vector<int> &numbers, vector<int> &digits) { digits.push_back(root->val); if(root->left == NULL && root->right == NULL) { int num = 0; for(int i = 0; i < digits.size(); i++) { num *= 10; num += digits[i]; } numbers.push_back(num); return; } if(root->left) { deep(root->left,numbers,digits); digits.pop_back(); } if(root->right) { deep(root->right,numbers,digits); digits.pop_back(); } } };