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链接:https://leetcode.com/problems/sum-root-to-leaf-numbers/
题目:一条roo->leaf路径代表一个整数,求所有整数之和
思路:先序遍历
代码:
class Solution {
public:
void pre(TreeNode *root,int sum){
if(!root) return;
if(!root->left&&!root->right) {
ret +=(sum *10 + root->val);
return ;
}
pre(root->left,root->val + sum * 10);
pre(root->right,root->val + sum * 10);
}
int sumNumbers(TreeNode* root) {
ret = 0;
pre(root,0);
return ret;
}
private:
int ret;
};