各种排序算法

年代有些久远了，但平时排序算法用得很多，所以汇总一下

各排序算法复杂度和稳定性的比较



C或c++实现

直接插入

void insert(int vector[],int n) {                     // 直接插入算法
int i, j, t;
for (i=1; i<n; i++) {
t=vector[i];
for(j=i-1; j>=0 && t<vector[j]; j--) {
vector[j+1] = vector[j];
}
vector[j+1] = t;
}
}

直接选择

Void select(int a[], int n) {                    // 直接选择算法

int i, j;
for(i = 0; i < n-1; i++) {
k=i;
for (j = i+1; j < n; j++)  if(a[k] > a[j])  k = j;
if(i != k) swap(a[k], a[i]);
}
}

冒泡排序

void bubble_sort(int a[],int n) {                // 冒泡排序算法：

int i, j;
for (i = 0; i < n-1; i++) {
for (j = 0; j < n-1-i; j++)
if (a[j] > a[j+1]) swap(a[j], a[j+1])
}
}

shell排序

// Shell 排序
void shellSort(int array[], int length)  {
int p, i, j, t;
for (p = length/2; p > 0; p /= 2) {
for (i = p; i < length; i++) {
for(j = i-p; j >= 0 && array[j] > array[j+p]; j -= p) {
t = array[j]; array[j] = array[j+p]; array[j+p] = t;
}
}
}
}

快速排序

void sort(int*a, int i, int j) {
int left, right, mid, t;
left = i; right = j;
mid = a[(i+j)/2];
do {
while (a[left] < mid) left++;
while (a[right] > mid) right--;
if (left <= right) {
t = a[left]; a[left] = a[right]; a[right] = t;
left++; right--;
}
} while (left <= right);
if (left < j) sort(a, left, j);
if (right > i) sort(a, i, right);
}

堆排序

#include<iostream>
using namespace std;

void Swap(int &a, int &b) {
int t = a;
a = b;
b = t;
}

void HeapAdjust(int s[], int start, int num) { // 调整为最大堆
int i, j;
while (2*start+1 < num) {
j = 2*start+1;
if (j+1 < num && s[j] < s[j+1]) j++;  // 选择左右子树中的较大者与父节点交换
if (s[start] < s[j]) {
Swap(s[start], s[j]);
start = j;  // 反复筛选
}
else break;
}
}

void HeapSort(int s[], int n) {
int i, j;
for (i = n/2-1; i >= 0; i--) HeapAdjust(s, i, n);  // 初始化最大堆
for (j = n-1; j >= 0; j--) {
Swap(s[0], s[j]);  // 通过交换堆顶元素与堆底元素达到取堆顶最大元素的目的
HeapAdjust(s, 0, j); // 对剩余j-1元素重新建成堆调整
}
}

int main() {
int a[12] = { 8, 2, 5, 43, 54, 1, 88, 23, 15, 99, 24, 33 };
HeapSort(a, 12);
for (int p = 0; p < 12; p++) cout << a[p] << " ";
cout << endl;
system("pause");
return 0;
}

归并排序

无递归：

#include<iostream>
#include<cstdio>
using namespace std;

void MergeStep(int a[], int r[], int s, int m, int n) {
int i = s, k = s, j = m+1;
while (i <= m &&j <= n) {
if (a[i] <= a[j]) r[k++] = a[i++];
else r[k++] = a[j++];
}
while (i <= m) r[k++] = a[i++];
while (j <= n) r[k++] = a[j++];
}

void MergePass(int a[], int r[], int n, int len) {
int s = 0, e;
while (s + len < n) {
e = s + 2 * len - 1;
if (e >= n) e = n - 1;
MergeStep(a, r, s, s + len - 1, e);
s = e + 1;
}
if (s < n) {
for (; s < n; s++) r[s] = a[s];
}
}

void MergeSort(int a[], int n) {
int *p;
int len = 1, f = 0;
p = (int*)malloc(sizeof(int)*n);
while (len < n) {
if (f) MergePass(p, a, n, len);
else MergePass(a, p, n, len);
len *= 2;
f = 1 - f;
}
if (f) {
for (f = 0; f < n; f++) a[f] = p[f];
}
free(p);
}
int main() {
int a[12] = { 8, 2, 5, 43, 54, 1, 88, 23, 15, 99, 24, 33 };
MergeSort(a, 12);
for (int p = 0; p < 12; p++) cout << a[p] << " ";
cout << endl;
system("pause");
return 0;
}

有递归：

void Merge(int a[], int low, int m, int high) {
// low为第1有序区的首元素， m为第1有序区的末元素
int *b = new int[high-low+1];
if (!b) {
cout << "ERROR!" << endl;
return;
}
int i = low, k = 0, j = m+1; // j（m+1）为第2有序区的首元素
while (i <= m && j <= high) {
if (a[i] <= a[j]) b[k++] = a[i++];
else b[k++] = a[j++];
}
while (i <= m) b[k++] = a[i++];
while (j <= high) b[k++] = a[j++];

for(i=low, k=0; i <= high; i++, k++) a[i]=b[k]; // //将排好序的存回数组a中low到high这区间
delete []b;
}

void Msort(int a[], int s, int t) {
int m = (s+t) /2;
if (s < t) {
Msort(a, s, m); // 左边
Msort(a, m+1, t); // 右边
Merge(a, s, m, t);
}
}