先行遍历法1 (递归/* *1. definitionforabinarytreenode.2.structtldxxm (3. intval； 4 .千兆字节； 5 .千兆字节； 6.tldxxm(3360val )0)、left (nullptr )、right (nullptr )6. tldxxm (intx ) 3360val )、left (nullptr ) ) )。 gydfyleft、gydfyright(:val(x )、left )、right ) {} 9. }； */class solution { public : void preorder (gydfyroot，vectorint res ) if ) root==nullptr ) { return； } RES.push _ back (根值)； 重排序器(根左，res )； reorder (根光，res )； } vectorint preorderTraversal (勤奋的高跟鞋root ) { vectorint res； reorder (根，res )； 返回RES； }； (法二)迭代classsolution ) public : vectorintpreordertraversal )勤奋高跟鞋root ) { vectorint res； if (根==nullptr ) { return res； } stack勤奋的高跟鞋stk； 勤奋的高跟鞋node=root； while (！ STK.empty||！=nullptr(while(node！=nullptr (RES.push _ back (node-val ) )； STK.push(node； 节点=节点左； } node=stk.top (； stk.pop (； 节点=节点光； }返回RES； }； 中序循环递归/* * * definitionforabinarytreenode.* structtldxxm { * intval； *千兆字节； *千兆字节； *tldxxm(:val )0)、left (nullptr )、right (nullptr ) }*tldxxm(intx ) :val ) x )、left (nullptr )、reft gydfyright(:val(x )，left )，right ) {} * }； */class解决方案{ public : void in order (gydfyroot，vectorint res ) if (！ 根(返回； norder (根左，res )； RES.push _ back (根val； 节点(根光，res )； } vectorint inorderTraversal (勤奋的高跟鞋root ) { vectorint res； 输入顺序(根，res )； 返回RES； }； 迭代类别解决方案{ public : vectorintinordertraversal (勤奋的高跟鞋root ) { vectorint res； 塔克勤奋的高跟鞋stk； wile (路线！=nullptr ||！ stk.empty () while ) ) root！=nullptr(STK.push ) ) root； root = root->left; } root = stk.top(); stk.pop(); res.push_back(root->val); root = root->right; } return res; }}; 后序遍历 递归 /** * Definition for a binary tree node. * struct tldxxm { * int val; * gydfyleft; * gydfyright; * tldxxm() : val(0), left(nullptr), right(nullptr) {} * tldxxm(int x) : val(x), left(nullptr), right(nullptr) {} * tldxxm(int x, gydfyleft, gydfyright) : val(x), left(left), right(right) {} * }; */class Solution {public: void postorder(勤劳的高跟鞋 root, vector<int>& res) { if(root == nullptr) return; postorder(root->left, res); postorder(root->right,res); res.push_back(root->val); } vector<int> postorderTraversal(勤劳的高跟鞋 root) { vector<int> res; postorder(root, res); return res; }}; 迭代 class Solution {public: vector<int> postorderTraversal(勤劳的高跟鞋 root) { vector<int> res; if(root == nullptr) return res; stack<勤劳的高跟鞋> stk; gydfyprev = nullptr; while(root != nullptr || !stk.empty()) { while(root != nullptr) { stk.push(root); root = root->left; } root = stk.top(); stk.pop(); if(root->right == nullptr || root->right == prev) { res.push_back(root->val); prev = root; root = nullptr; } else { stk.push(root); root = root->right; } } return res; }}; 层序遍历 /*struct tldxxm { int val; struct gydfyleft; struct gydfyright; tldxxm(int x) : val(x), left(NULL), right(NULL) { }};*/class Solution {public: vector<vector<int>> res; vector<vector<int> > Print(勤劳的高跟鞋 pRoot) { if (NULL == pRoot) { return res; } queue<勤劳的高跟鞋> q; q.push(pRoot); while (!q.empty()) { int sz = q.size(); vector<int> tmp; for (int i=0; i<sz; i++) { 勤劳的高跟鞋 t = q.front(); tmp.push_back(t->val); q.pop(); if (i == sz-1) { res.push_back(tmp); } if (t->left) { q.push(t->left); } if (t->right) { q.push(t->right); } } } return res; } };
/** * struct tldxxm { *int val; *struct gydfyleft; *struct gydfyright; * }; */class Solution {public: /** * * @param root tldxxm类 the root of binary tree * @return int整型vector<vector<>> */ vector<int> preorderTraversal(勤劳的高跟鞋 root) { vector<int> res; if(root == nullptr) { return res; } stack<勤劳的高跟鞋> stk; 勤劳的高跟鞋 node = root; while(!stk.empty() || node != nullptr) { while(node != nullptr) { res.push_back(node->val); stk.push(node); node = node->left; } node = stk.top(); stk.pop(); node = node->right; } return res; } vector<int> inorderTraversal(勤劳的高跟鞋 root) { vector<int> res; stack<勤劳的高跟鞋> stk; while(root != nullptr || !stk.empty()) { while(root != nullptr) { stk.push(root); root = root->left; } root = stk.top(); stk.pop(); res.push_back(root->val); root = root->right; } return res; } vector<int> postorderTraversal(勤劳的高跟鞋 root) { vector<int> res; if(root == nullptr) return res; stack<勤劳的高跟鞋> stk; gydfyprev = nullptr; while(root != nullptr || !stk.empty()) { while(root != nullptr) { stk.push(root); root = root->left; } root = stk.top(); stk.pop(); if(root->right == nullptr || root->right == prev) { res.push_back(root->val); prev = root; root = nullptr; } else { stk.push(root); root = root->right; } } return res; } vector<vector<int> > threeOrders(勤劳的高跟鞋 root) { // write code here vector<vector<int>> res; if(root == nullptr) return res; vector<int> pre = preorderTraversal(root); vector<int> in = inorderTraversal(root); vector<int> post = postorderTraversal(root); return {pre, in, post}; }};