29 lines
1.0 KiB
C++
29 lines
1.0 KiB
C++
struct TreeNode {
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int val;
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TreeNode* left;
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TreeNode* right;
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explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(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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* Refer: 220111.cpp
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*/
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class Solution {
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public:
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int sumRootToLeaf(TreeNode* root, int sum = 0) {
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if (!root)
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return 0;
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const int ans = (sum << 1) + root->val;
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if (!root->left && !root->right)
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return ans;
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return sumRootToLeaf(root->left, ans) + sumRootToLeaf(root->right, ans);
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}
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};
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