根据先序和中序遍历求后续遍历
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
//代码附有测试部分 可以清楚地了解到每一步的输出结果 #include <string.h> #include <stdio.h> /*void build(int n,char *s1,char *s2,char *s) { if(n<=0) return; int p=strchr(s2,s1[0])-s2;//找到根结点在中序遍历中的位置 build(p,s1+1,s2,s);//递归构造左子树的后序遍历 build(n-p-1,s1+p+1,s2+p+1,s+p);//递归构造右子树的后序遍历 s[n-1]=s1[0];//把根结点添加到最后 }*/ void build(int n, char* s1, char* s2, char* s) { if(n <= 0) return; int p = strchr(s2, s1[0]) - s2; printf("%d\n",p); build(p, s1+1, s2, s); build(n-p-1, s1+p+1, s2+p+1, s+p); printf("s1[0]:%c\n",s1[0]); printf("s2[0]:%c\n",s2[0]); s[n-1] = s1[0]; } int main() { char s1[100],s2[100],ans[100]; while(scanf("%s%s",s1,s2)==2) { int n=strlen(s1); build(n,s1,s2,ans); ans[n]='\0'; printf("%s",ans); } return 0; }