PAT 1012Invert a Binary Tree反转二叉树（反转树，层序，中序）

传送

题目给定一颗二叉树，要求输出反转后二叉树的层序遍历序列和中序遍历序列

关于反转操作，后序或者先序都可以

#include
#define rep(i,a,n) for(int i=a;inode[N];
vectorans,res;
void gao(int root){
    if(root==-1) return ;
    gao(node[root].x);
    gao(node[root].y);
    swap(node[root].x,node[root].y);
}
void bfs(int root){
    queueq;
    q.push(root);
    while(!q.empty()){
        int p=q.front();
        q.pop();
        ans.push_back(p);
        if(node[p].x!=-1) q.push(node[p].x);
        if(node[p].y!=-1) q.push(node[p].y);
    }
    rep(i,0,ans.size())
        printf("%d%c",ans[i],i==ans.size()-1?'\n':' ');
}

void dfs(int root){
    if(node[root].x!=-1)dfs(node[root].x);
    res.push_back(root);
    if(node[root].y!=-1)dfs(node[root].y);
    return ;
}
int vis[N];
int main(){
    cin>>n;
    rep(i,0,n) {
        char a,b;
        cin>>a>>b;
        if(a!='-') node[i].x=a-'0',vis[a-'0']=1;
        else node[i].x=-1;
        if(b!='-') node[i].y=b-'0',vis[b-'0']=1;
        else node[i].y=-1;
    }
    int root=0;
    while(vis[root]) root++;
    gao(root);
    bfs(root);
    dfs(root);
    rep(i,0,res.size())
        printf("%d%c",res[i],i==res.size()-1?'\n':' ');
      
    return 0;
}