Vijos1132:求二叉树的先序序列

#include <cstdio>
#include <cstring>
using namespace std;
const int MAXN=10;
char in_order[MAXN];
char post_order[MAXN];
char pre_order[MAXN];
void build(int l1,int r1,int l2,int r2)
{
    if(l1>r1)
        return ;
    char root=post_order[r2];
    int p=l1;
    while(in_order[p]!=root)    p++;
    printf("%c",root);
    int cnt=p-l1;
    build(l1,p-1,l2,l2+cnt-1);//左子树
    build(p+1,r1,l2+cnt,r2-1);//右子树
}
int main()
{
    scanf("%s",in_order);
    scanf("%s",post_order);
    int len=strlen(in_order);
    build(0,len-1,0,len-1);
    return 0;
}