PKU 2255 Tree Recovery(二叉树)

前中求后

rt需在pre里面找

#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <map>#include <queue>#include <string>#include <set>#include <vector>using namespace std;const int N=27,INF=0x3f3f3f3f;char in[N],pre[N];int n,k;void dfs(int l,int r,int rt){    int i;    for(i=l;in[i]!=pre[rt];i++);    if(l<=i-1) dfs(l,i-1,rt+1);//l,i->in[]  rt->pre[]     if(i+1<=r) dfs(i+1,r,rt+i-l+1);    k==0?printf("%c",in[i]):printf(" %c",in[i]);}int main(){    while(~scanf("%s %s",pre,in))    {        k=0;        dfs(0,strlen(pre)-1,0);        puts("");    }}