PAT1064. Complete Binary Search Tree

1064. Complete Binary Search Tree

题目大意

给定一个序列, 求其 生成Complete BST 的层序遍历.

思路

最开始把这个题想复杂了, 还想着建立结构体, 其实用数组最为方便简单

1. 中序遍历这棵 Complete BST, 依次填入一个排好序的序列.
2. 因为是数组存放, 所以直接输出 1 - nNode 就好.

代码

#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#define MAXN 2000
using namespace std;
int nNode;
int curSeq = 0;
vector<int> seq;
int arr[MAXN];
void dfs(int root){
    if(root > nNode)
        return;
    dfs(root << 1);
    arr[root] = seq[curSeq++];
    dfs(root << 1 | 1);
}
int main(){
    scanf("%d", &nNode);
    seq.resize(nNode);
    for(int i = 0; i < nNode; i++)
        scanf("%d", &seq[i]);
    sort(seq.begin(), seq.end());
    dfs(1);

    for(int i = 1; i <= nNode; i++){
        if(i != 1) printf(" ");
        printf("%d", arr[i]);
    }
    return 0;
}