L2-011. 玩转二叉树

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>
#include <queue>
using namespace std;
const int maxn = 1e3+5;
int a[maxn];
int b[maxn];
int floor1[maxn];
int tr[maxn<<2];
int retr[maxn<<2];
int n;
void build(int x,int al,int ar,int bl,int br)
{
if(ar<al||br<bl) return;
if(al == ar)
{
tr[x] = a[al];
return;
}
for(int i = 1; i<=n; i++)
{
if(a[i]==b[bl])
{
tr[x] = a[i];
build(2*x,i+1,ar,bl+i-al+1,br);   //只需要将之前的代码上下两句调换即可。
build(2*x+1,al,i-1,bl+1,bl+i-al);

break;
}
}
}

void bfs(int x)  //按层序遍历
{
queue<int> q;
q.push(x);
int ans = 1;
while(!q.empty())
{
int y = q.front();
q.pop();
if(tr[y]==0) continue;
floor1[ans++] = tr[y];
q.push(2*y);
q.push(2*y+1);
}
}
int main()
{
memset(tr,0,sizeof(tr));
scanf("%d",&n);
for(int i = 1; i<=n; i++)
{
scanf("%d",&a[i]);
}
for(int i = 1; i<=n; i++)
{
scanf("%d",&b[i]);
}
build(1,1,n,1,n);
retr[1] = tr[1];
bfs(1);
for(int i = 1; i<n; i++) printf("%d ",floor1[i]);
printf("%d\n",floor1
);
return 0;
}