37 lines
753 B
C++
37 lines
753 B
C++
#include <vector>
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#include <queue>
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#include <utility>
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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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explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
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};
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class Solution {
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public:
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std::vector<std::vector<int>> levelOrder(TreeNode* root) {
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if (!root)
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return {};
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std::vector<std::vector<int>> ret {{}};
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std::queue<std::pair<const TreeNode*, int>> q;
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q.push({root, 0});
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int cl = 0;
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while (!q.empty()) {
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const auto [v, l] = q.front();
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q.pop();
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if (l > cl) {
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++cl;
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ret.emplace_back();
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}
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ret.back().push_back(v->val);
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if (v->left)
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q.push({v->left, 1 + l});
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if (v->right)
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q.push({v->right, 1 + l});
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}
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return ret;
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}
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}; |