PAT A1102 Invert a Binary Tree （25 分）——静态树，层序遍历，先序遍历，后序遍历

The following is from Max Howell @twitter:

Google: 90% of our engineers use the software you wrote (Homebrew), but you can't invert a binary tree on a whiteboard so fuck off.

Now it's your turn to prove that YOU CAN invert a binary tree!

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N (≤10) which is the total number of nodes in the tree -- and hence the nodes are numbered from 0 to N−1. Then N lines follow, each corresponds to a node from 0 to N−1, and gives the indices of the left and right children of the node. If the child does not exist, a - will be put at the position. Any pair of children are separated by a space.

Output Specification:

For each test case, print in the first line the level-order, and then in the second line the in-order traversal sequences of the inverted tree. There must be exactly one space between any adjacent numbers, and no extra space at the end of the line.

Sample Input:

8
1 -
- -
0 -
2 7
- -
- -
5 -
4 6

Sample Output:

3 7 2 6 4 0 5 1
6 5 7 4 3 2 0 1

 #include <stdio.h>
 #include <algorithm>
 #include <set>
 #include <string.h>
 #include <vector>
 #include <queue>
 using namespace std;
 struct node{
     int data;
     int l=-,r=-;
 };
 const int maxn = ;
 int n;
 node tree[maxn];
 int vis[maxn]={};
 void lvl(int root){
     queue<int> q;
     q.push(root);
     int cnt=;
     while(!q.empty()){
         int now=q.front();
         q.pop();
         cnt++;
         if(cnt<n)printf("%d ",now);
         else printf("%d\n",now);
         if(tree[now].r!=-)q.push(tree[now].r);
         if(tree[now].l!=-)q.push(tree[now].l);
     }
 }
 int cnt=;
 void ino(int root){
     if(root==-)return;
     if(tree[root].r!=-) ino(tree[root].r);
     cnt++;
     if(cnt<n)printf("%d ",root);
     else printf("%d",root);
     if(tree[root].l!=-) ino(tree[root].l);
 }
 int main(){
     scanf("%d",&n);
     getchar();
     for(int i=;i<n;i++){
         char c1,c2;
         scanf("%c %c",&c1,&c2);
         getchar();
         int l=-,r=-;
         if(c1!='-'){
             l=c1-'';
             vis[l]=;
         }
         if(c2!='-'){
             r=c2-'';
             vis[r]=;
         }
         tree[i].l=l;
         tree[i].r=r;
         tree[i].data=i;

     }
     int root;
     for(int i=;i<n;i++){
         if(vis[i]==){
             root=i;
             break;
         }
     }
     lvl(root);
     ino(root);
 }

注意点：又是读字符出现了错误，注意换行符一定要用getchar吃掉，不然会被%c认为是输入字符。别的就是普通的树的遍历