数据结构-2020夏 04-树6 Complete Binary Search Tree (30分)

 

原题地址

https://pintia.cn/problem-sets/1268384564738605056/problems/1276814005115539458

解题思路

听了姥姥讲的小白专场之后做出来的~

一开始也有想到求这个结点的方法，但是没有考虑递归，所以做错了！

默默咕哝：树和递归szd好朋友QWQ

参考代码

#include 
using namespace std;
#define pb push_back
typedef double db;
typedef long long LL;
typedef vector VI;
const int inf = 2e9;
const LL INF = 8e18;
const int maxn = 1e3 + 10;
int A[maxn], T[maxn];

int compare(const void*a, const void*b) {
	return *(int*)a - *(int*)b;
}

int getLeftLength(int n) {
	int H, L, X;
	H = int(log(n + 1) / log(2));
	int num = pow(2, H);
	X = n - (num - 1);
	L = num/2 - 1 + min(X, num/2);
	return L;
}

//从数组A中选出正确的填入T[TRoot]中 
void solve(int ALeft, int ARight, int TRoot) {
	//初始调用为solve(0, n-1, 0) 
	int n = ARight - ALeft + 1;
	//递归边界，数填完 
	if (n == 0) return;
	int L = getLeftLength(n);  //计算n个结点的树其左子树有几个结点
	T[TRoot] = A[ALeft + L];
	int LeftRoot = TRoot * 2 + 1; 
	int RightRoot = LeftRoot + 1; 
	solve(ALeft, ALeft + L - 1, LeftRoot);
	solve(ALeft + L + 1, ARight, RightRoot);
}

int main() {
	int n;
	scanf("%d", &n);
	for (int i = 0; i < n; ++i) {
		scanf("%d", &A[i]);
	}
	qsort(A, n, sizeof(int), compare);
	solve(0, n - 1, 0);
	for (int i = 0; i < n; ++i) {
		if (i) printf(" ");
		printf("%d", T[i]);
	}
	return 0;
}