PAT 1064 Complete Binary Search Tree
1 #include <iostream> 2 #include <cstdio> 3 #include <cstdlib> 4 #include <vector> 5 #include <algorithm> 6 7 using namespace std; 8 9 class Node { 10 public: 11 int val; 12 Node* left; 13 Node* right; 14 public: 15 Node(): val(0), left(NULL), right(NULL) {} 16 Node(int _val, Node* _left = NULL, Node* _right = NULL): val(_val), left(_left), right(_right) {} 17 }; 18 19 vector<Node*> build_next_level(vector<Node*> last_level, int &num) { 20 vector<Node*> res; 21 if (num < 1) return res; 22 23 for (auto iter = last_level.begin(); iter != last_level.end(); iter++) { 24 Node* parent = *iter; 25 26 Node* lchild = new Node(); 27 res.push_back(lchild); 28 parent->left = lchild; 29 if (--num < 1) break; 30 31 Node* rchild = new Node(); 32 res.push_back(rchild); 33 parent->right= rchild; 34 if (--num < 1) break; 35 } 36 37 return res; 38 } 39 40 void inorder_traverse(Node* root, int& order) { 41 if (root == NULL) return; 42 inorder_traverse(root->left, order); 43 root->val = order++; 44 inorder_traverse(root->right, order); 45 } 46 47 int main() { 48 int cnt; 49 50 scanf("%d", &cnt); 51 52 vector<int> nums(cnt, 0); 53 54 if (cnt < 1) return 0; 55 56 for (int i = 0; i<cnt; i++) { 57 int num = 0; 58 scanf("%d", &num); 59 nums[i] = num; 60 } 61 sort(nums.begin(), nums.end()); 62 63 vector<vector<Node*> > levels; 64 65 vector<Node*> last_level; 66 last_level.push_back(new Node()); 67 68 levels.push_back(last_level); 69 70 int node_cnt = cnt - 1; // we already pushed the root node 71 while (node_cnt > 0) { 72 vector<Node*> cur_level = build_next_level(last_level, node_cnt); 73 levels.push_back(cur_level); 74 swap(last_level, cur_level); 75 } 76 77 int order = 0; 78 inorder_traverse(levels[0][0], order); 79 80 node_cnt = cnt; 81 82 for (auto iter_levels = levels.begin(); iter_levels != levels.end(); iter_levels++) { 83 vector<Node*>& cur_level = *iter_levels; 84 for (auto iter = cur_level.begin(); iter != cur_level.end(); iter++) { 85 Node* node = *iter; 86 int val = nums[node->val]; 87 if (--node_cnt > 0) { 88 printf("%d ", val); 89 } else { 90 printf("%d\n", val); // last element 91 } 92 } 93 } 94 return 0; 95 }
又是跟书本比较近的一题
