总结了一下排序算法
以函数式写法为主,比较统一形式
#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> a;
// 冒泡排序
void bubblesort(vector<int>& a, int n) {
for (int i = n - 1; i > 0; i -- ) {
for (int j = 0; j < i; j ++ ) {
if (a[j] > a[j + 1]) swap(a[j], a[j + 1]);
}
}
}
// 快速排序
void quicksort(vector<int>& a, int l, int r) {
if (l >= r) return ;
int i = l - 1, j = r + 1, mid = a[l + r >> 1];
while (i < j) {
do i ++ ; while (a[i] < mid) ;
do j -- ; while (a[j] > mid) ;
if (i < j) swap(a[i], a[j]);
}
quicksort(a, l, j);
quicksort(a, j + 1, r);
}
// 归并排序
vector<int> tmp;
void mergesort(vector<int>& a, int l, int r) {
if (l >= r) return ;
int mid = l + r >> 1;
mergesort(a, l, mid);
mergesort(a, mid + 1, r);
int k = 0, i = l, j = mid + 1;
while (i <= mid && j <= r) {
if (a[i] < a[j]) tmp[k ++ ] = a[i ++ ];
else tmp[k ++ ] = a[j ++ ];
}
while (i <= mid) tmp[k ++ ] = a[i ++ ];
while (j <= r) tmp[k ++ ] = a[j ++ ];
for (int i = l, j = 0; i <= r; i ++ , j ++ ) a[i] = tmp[j];
}
// 堆排序
void down(int x, int cnt) {
int t = x;
if (2 * x <= cnt && a[2 * x] < a[x]) t = 2 * x;
if (2 * x + 1 <= cnt && a[2 * x + 1] < a[x]) t = 2 * x + 1;
if (t != x) {
swap(a[t], a[x]);
down(t, cnt);
}
}
void heapsort(vector<int>& a, int n) {
int cnt = n;
for (int i = n / 2; i >= 0; i -- ) down(i, cnt);
while (n -- ) {
cout << a[1] << ' ';
a[1] = a[cnt];
cnt -- ;
down(1, cnt);
}
}
int main() {
cin >> n;
a.resize(n);
for (int i = 0; i < n; i ++ ) cin >> a[i];
// bubblesort(a, n);
// quicksort(a, 0, n - 1);
// tmp.resize(n);mergesort(a, 0, n - 1);
// heapsort(a, n);
for (int i = 0; i < n; i ++ ) cout << a[i] << ' ';
cout << endl;
return 0;
}