41 lines
1.5 KiB
C++
41 lines
1.5 KiB
C++
#include <iostream>
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// Definition for a binary tree node.
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struct TreeNode {
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int val;
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TreeNode *left;
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TreeNode *right;
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TreeNode() : val(0), left(nullptr), right(nullptr) {}
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explicit TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
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TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
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~TreeNode() { delete this->left; delete this->right; }
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};
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/**
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* 1022. Sum of Root To Leaf Binary Numbers
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* You are given the root of a binary tree where each node has a value 0 or 1. Each root-to-leaf path represents a binary number starting with the most significant bit.
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* For example, if the path is 0 -> 1 -> 1 -> 0 -> 1, then this could represent 01101 in binary, which is 13.
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* For all leaves in the tree, consider the numbers represented by the path from the root to that leaf. Return the sum of these numbers.
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* The test cases are generated so that the answer fits in a 32-bits integer.
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*/
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class Solution {
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public:
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static int sumRootToLeaf(const TreeNode* root, int n = 0) {
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if (!root->left && !root->right)
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return n + root->val;
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int ret = 0;
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if (root->left)
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ret += sumRootToLeaf(root->left, (n + root->val) << 1);
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if (root->right)
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ret += sumRootToLeaf(root->right, (n + root->val) << 1);
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return ret;
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}
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};
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int main() {
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TreeNode head(1, new TreeNode(0, new TreeNode(0), new TreeNode(1)), new TreeNode(1, new TreeNode(0), new TreeNode(1)));
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std::cout << Solution::sumRootToLeaf(&head);
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return 0;
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}
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