PAT 1099. Build A Binary Search Tree (30) 叒掉语言陷阱！！

1099. Build A Binary Search Tree (30)

时间限制

100 ms

内存限制

65536 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

A Binary Search Tree (BST) is recursively defined as a binary tree which has the following properties:

The left subtree of a node contains only nodes with keys less than the node's key.

The right subtree of a node contains only nodes with keys greater than or equal to the node's key.

Both the left and right subtrees must also be binary search trees.

Given the structure of a binary tree and a sequence of distinct integer keys, there is only one way to fill these keys into the tree so that the resulting tree satisfies the definition of a BST. You are supposed to output the level order traversal sequence of that tree. The sample is illustrated by Figure 1 and 2.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N (<=100) which is the total number of nodes in the tree. The next N lines each contains the left and the right children of a node in the format "left_index right_index", provided that the nodes are numbered from 0 to N-1, and 0 is always the root. If one child is missing, then -1 will represent the NULL child pointer. Finally N distinct integer keys are given in the last line.

Output Specification:

For each test case, print in one line the level order traversal sequence of that tree. All the numbers must be separated by a space, with no extra space at the end of the line.

Sample Input:

91 62 3-1 -1-1 45 -1-1 -17 -1-1 8-1 -173 45 11 58 82 25 67 38 42

Sample Output:

58 25 82 11 38 67 45 73 42

建树那里，并不是按中序遍历来的！是按序号。

#include <iostream>#include<stdio.h>#include<string>#include<queue>#include<algorithm>#include<string.h>#include<vector>#include<map>#include<math.h>using namespace std;int n;struct{   int lc,rc=-1;   int value;}node[105];int value[105];int p=0;void buildtree(int now) {       //   int x,y;       //   cin>>x>>y;       //   node[now].lc=x;       //   node[now].rc=y;       //   if(node[now].lc!=-1) buildtree(x);       //   if(node[now].rc!=-1) buildtree(y);       for(int i=0;i<n;i++)       {           int x,y;           cin>>x>>y;           node[i].lc=x;           node[i].rc=y;       } } void preorder(int x) {     if(node[x].lc!=-1) preorder(node[x].lc);     node[x].value=value[p++];     if(node[x].rc!=-1) preorder(node[x].rc); } void levelorder() {     queue<int> Q;     Q.push(0);     int flag=0;     while(!Q.empty())     {         int tmp=Q.front();         Q.pop();         if(flag==1) cout<<' ';         flag=1;         cout<<node[tmp].value;         if(node[tmp].lc!=-1) Q.push(node[tmp].lc);         if(node[tmp].rc!=-1) Q.push(node[tmp].rc);     } }int main(){    cin>>n;    buildtree(0);    for(int i=0;i<n;i++)    cin>>value[i];    sort(value,value+n);    preorder(0);    levelorder();    return 0;}