PAT (Advanced Level) 1102. Invert a Binary Tree (25)

简单题。

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<map>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;

struct Node
{
    int left;
    int right;
}s[];
int n;
vector<int>ans1,ans2;
int flag[];
int root;

void bfs()
{
    queue<int>q; q.push(root);
    while(!q.empty())
    {
        int h=q.front(); q.pop();
        ans1.push_back(h);
        if(s[h].left!=-) q.push(s[h].left);
        if(s[h].right!=-) q.push(s[h].right);
    }
}

void dfs(int x)
{
    if(s[x].left!=-) dfs(s[x].left);
    ans2.push_back(x);
    if(s[x].right!=-) dfs(s[x].right);
}

int main()
{
    memset(flag,,sizeof flag);
    scanf("%d",&n);
    for(int i=;i<n;i++)
    {
        char L[],R[];
        scanf("%s%s",L,R);
        if(L[]=='-') s[i].left=-;
        else
        {
            s[i].left=L[]-'';
            flag[L[]-'']=;
        }
        if(R[]=='-') s[i].right=-;
        else
        {
            s[i].right=R[]-'';
            flag[R[]-'']=;
        }
    }

    for(int i=;i<n;i++)
        if(flag[i]==) root=i;

    for(int i=;i<n;i++)
        swap(s[i].left,s[i].right);

    bfs();
    dfs(root);
    for(int i=;i<ans1.size();i++)
    {
        printf("%d",ans1[i]);
        if(i<ans1.size()-) printf(" ");
        else printf("\n");
    }

    for(int i=;i<ans1.size();i++)
    {
        printf("%d",ans2[i]);
        if(i<ans2.size()-) printf(" ");
        else printf("\n");
    }

    return ;
}