排序算法

//
//  main.cpp
//  1.1排序_冒泡排序
//
//  Created by lujunjie on 2016/12/25.
//  Copyright © 2016年 陆俊杰. All rights reserved.
//

#include <iostream>
using namespace std;
int* bubbleSort(int* A, int n);
int main(int argc, const char * argv[]) {
    // 升序 操作：
    // 第一轮，从0元素开始与相邻元素对比，大的往后放,直到把最大值放到 len - 1 位置
    // 第二轮，从0开始与相邻元素对比，把最大值放到len - 1 - i 位置
    // ** len - 1; 倒数第二跟最后值对比
    // ** len - 1 - i; 比较过得无需再对比
    int arr[8] = {5,33,66,77,11,44,55,22};
    int len = 8;
    for (int i = 0; i< len - 1; i++) {
        
        for (int j = 0; j< len - 1 - i; j++) {
            
            if (arr[j] > arr[j+1]) {
                int tmp = arr[j];
                arr[j] = arr[j+1];
                arr[j+1] = tmp;
            }
        }
    }
    
    for (int i = 0; i< len; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
    
    return 0;
}

//
//  main.cpp
//  1.2排序_插入排序
//
//  Created by lujunjie on 2016/12/25.
//  Copyright © 2016年 陆俊杰. All rights reserved.
//

#include <iostream>
using namespace std;
int main(int argc, const char * argv[]) {
    
    int arr[13] = {54,35,48,36,27,12,44,44,8,14,26,17,28};
    int len = 13;
    for (int i = 0; i< len-1; i++) {
        if (arr[i] > arr[i+1]) {
            int index = i;
            int value = arr[i+1];
            while (value < arr[index]) {// 移动位置
                arr[index + 1] = arr[index];
                index--;
                if (index< 0) {// 判断到[0]
                    break;
                }
            }
            arr[index+1] = value;// 插入原来判断的哪个元素。
        }
    }
    
    for (int i = 0; i< len; i++) {
        std::cout << arr[i] << " ";
    }
    
    return 0;
}

//
//  main.cpp
//  1.3排序_选择排序
//
//  Created by lujunjie on 2016/12/25.
//  Copyright © 2016年 陆俊杰. All rights reserved.
//

#include <iostream>
using namespace std;
int selectMinKey(int *arr,int from,int to)
{
    int index = from;
    for (int i = from + 1; i<to; i++) {
        if (arr[index] > arr[i]) {
            index = i;
        }
    }
    return index;
}

int main(int argc, const char * argv[]) {
   
    int arr[8] = {5,33,66,77,11,44,55,22};
    int len = 8;
    
    
    for (int i = 0; i< len; i++) {
        
        int min = i;
        for (int j = i + 1; j < len; j++) {
            if (arr[min] >  arr[j]) {
                min = j;
            }
        }
        
        if (min!=i) {
            swap(arr[min], arr[i]);
        }
    }
    for (int i = 0; i< len; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
    return 0;
}

//
//  main.cpp
//  1.4排序_快速排序
//
//  Created by lujunjie on 2016/12/26.
//  Copyright © 2016年 陆俊杰. All rights reserved.
//

#include <iostream>
// 4 high = [2] low = [2]
// 2 3 4 5 6 8
using namespace std;
int partition(int *pArr,int arrlen,int low,int high)
{
    // 保存标准值
    int standardVal = pArr[low];
    while (low < high) {
        while (low < high && pArr[high] >= standardVal) {
            high--;
        }
        if (low < high) {
            swap(pArr[low], pArr[high]);
        }
        while (low < high && pArr[low] <= standardVal) {
            low++;
        }
        if (low < high) {
            swap(pArr[low], pArr[high]);
        }
    }
    return low;
}
void quickSortImpl(int *pArr,int arrLen,int low,int high)
{
    if (low < high) {
        // 第一步：找到中间值
        int centerPoint = partition(pArr,arrLen,low,high);
        
        // 第二步：前半部分排序
        quickSortImpl(pArr, arrLen, low, centerPoint-1);
        
        //第三步：后半部分排序
        quickSortImpl(pArr, arrLen, centerPoint+1, high);
        
    }
}

int main(int argc, const char * argv[]) {
    
    int a[15] = {54,35,48,36,27,12,44,44,8,14,26,17,28,999,11};
    int size = 15;
    quickSortImpl(a, size, 0, size-1);
    for (int i = 0; i < size; i++) {
        std::cout << a[i] << " ";
    }

    return 0;
}