PAT(A) 1086

来源：互联网发布：事情进度跟踪软件编辑：程序博客网时间：2024/05/21 03:24

push的顺序即为先序遍历

pop的顺序为中序遍历

根据先序遍历和中序遍历求后序遍历

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<stack>#include<vector> using namespace std;stack<int> s1;void PreAndIn(int inorder[],int preorder[],int n){if(n == 0)return ;int root;root = preorder[0];int i;for(i = 0;i<n;i++)if(inorder[i] == root)break;s1.push(root);PreAndIn(inorder + i+1,preorder + i+1,n-i-1);//右子树先递归，先进stack实现postorder PreAndIn(inorder,preorder+1,i);}int main(){int i,j,pp,ip;char str[10];int n,num;int preorder[35],inorder[35];//FILE *fp;//fp = fopen("1.in","r");fscanf(stdin,"%d",&n);stack<int> s;pp = ip = 0;int count = 0;while(count<n){fscanf(stdin,"%s",str);if(!strcmp(str,"Push")){fscanf(stdin,"%d",&num);preorder[pp++] = num;s.push(num);}else {num = s.top();s.pop();inorder[ip++] = num;count++;}}//for(i = 0;i<n;i++)//printf("%d ",preorder[i]);//printf("\n");//for(i = 0;i<n;i++)//printf("%d ",inorder[i]);PreAndIn(inorder,preorder,n);for(i = 0;i<n;i++){printf("%d",s1.top());s1.pop();if(i == n-1)printf("\n");else printf(" ");}return 0;}

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