Homework Introduction

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int n, a[N], b[N];

void bubblesort() {
	for (int i = 1; i < n; i++) {
		for (int j = 1; j <= n - i; j++) {
			if (a[j] > a[j + 1]) {
				swap(a[j], a[j + 1]);
			}
		}
	}
}

void selectsort() {
	for (int i = 1; i < n; i++) {
		//从i~n最小的数
		int id = 0, minn = 1e9 + 5;
		for (int j = i; j <= n; j++) {
			if (a[j] < minn) {
				minn = a[j];
				id = j;
			}
		}
		swap(a[i], a[id]);
	}
}

void insertsort() {
	for (int i = 2; i <= n; i++) {
		//将a[i]插入进去
		int tmp = a[i], j = i - 1;
		while (a[j] > tmp && j >= 1) {
			a[j + 1] = a[j];
			j--;
		}
		a[j + 1] = tmp;
	}
}

void quicksort(int l, int r) {
	if (l >= r)
		return;
	//取基准数
	int mid = rand() % (r - l) + l;
	swap(a[mid], a[l]);
	int tmp = a[l];
	int i = l, j = r;
	while (i < j) {
		//1.从右往左找比tmp小的
		while (i < j && a[j] >= tmp)
			j--;
		//2.从左往右找比tmp大的
		while (i < j && a[i] <= tmp)
			i++;
		swap(a[i], a[j]);
	}
	swap(a[l], a[i]);
	quicksort(l, i - 1);
	quicksort(i + 1, r);
}

void mergesort(int l, int r) {
	if (l >= r)
		return;
	int mid = (l + r) >> 1;
	mergesort(l, mid);
	mergesort(mid + 1, r);
	int i = l, j = mid + 1, cnt = l - 1;
	while (i <= mid && j <= r) {
		if (a[i] < a[j]) {
			b[++cnt] = a[i++];
		} else
			b[++cnt] = a[j++];
	}
	while (i <= mid)
		b[++cnt] = a[i++];
	while (j <= r)
		b[++cnt] = a[j++];
	for (int i = l; i <= r; i++) {
		a[i] = b[i];
	}

}

void Down(int rt, int size) {
	int lc = rt << 1;
	int rc = rt << 1 | 1;
	int maxx = rt;
	if (lc <= size && a[lc] > a[maxx])
		maxx = lc;
	if (rc <= size && a[rc] > a[maxx])
		maxx = rc;
	if (maxx != rt) {
		swap(a[maxx], a[rt]);
		Down(maxx, size);
	}
}

void buildheap() {
	for (int i = n / 2; i >= 1; i--) {
		Down(i, n);
	}
}

void heapsort() {
	buildheap();
	for (int i = n; i >= 1; i--) {
		swap(a[i], a[1]);
		Down(1, i - 1);
	}
}

int main() {
	srand(time(0));
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
//	bubblesort();
//	selectsort();
//	insertsort();
//	quicksort(1, n);
//	mergesort(1, n);
	heapsort();
	for (int i = 1; i <= n; i++) {
		cout << a[i] << " ";
	}
	return 0;
}
Status
Done
Problem
1
Open Since
2025-9-20 0:00
Deadline
2025-9-27 23:59
Extension
24 hour(s)