zoukankan      html  css  js  c++  java
  • 1138 Postorder Traversal (25分)

    Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder traversal sequence of the corresponding binary tree.

    Input Specification:

    Each input file contains one test case. For each case, the first line gives a positive integer N (≤ 50,000), the total number of nodes in the binary tree. The second line gives the preorder sequence and the third line gives the inorder sequence. All the numbers in a line are separated by a space.

    Output Specification:

    For each test case, print in one line the first number of the postorder traversal sequence of the corresponding binary tree.

    Sample Input:

    7
    1 2 3 4 5 6 7
    2 3 1 5 4 7 6
    
     

    Sample Output:

    3

    已知先序中序求后序

    #include <iostream>
    using namespace std;
    int pre[99999], in[99999], post[99999], c = 0, N;
    void postorder(int root, int start, int end) {
        if(start > end) return;
        int i = start;
        while(i < end && in[i] != pre[root]) i++;
        postorder(root + 1, start, i - 1);
        postorder(root + 1, i + 1, end);
        post[c++] = in[i];
    }
    int main() {
        scanf("%d", &N);
        for(int i = 0; i < N; i++)
            scanf("%d", &pre[i]);
        for(int i = 0; i < N; i++)
            scanf("%d", &in[i]);
        postorder(0, 0, N - 1);
        printf("%d", post[0]);
        return 0;
    }
  • 相关阅读:
    python的dict和set
    python基础之dict和set
    python基础之条件判断和循环
    mongodb安装和配置,遇到问题和解决方法
    mybatis12--一级缓存
    mybatis11--多对多关联查询
    mybatis10--自连接多对一查询
    mybatis09--自连接一对多查询
    mybatis08--关联查询多对一
    mybatis07--关联查询一对多
  • 原文地址:https://www.cnblogs.com/littlepage/p/12822433.html
Copyright © 2011-2022 走看看