基础排序算法

快速排序

# 快速排序
void QuickSort(int *array, int start, int end){

    if(start > end || array == NULL)
        return;
    
    int pivot = array[start];
    int left = start;
    int right = end;
    
    while(right > left){
       
       while(right > left && array[right] >= pivot)
           --right;
       
       array[left] = array[right];
       
       while(right > left && pivot >= array[left])
           ++left;
       
       array[right] = array[left];
       array[left] = pivot;
    }
   
    QuickSort(array, start, left-1);
    QuickSort(array, left+1, end);
}
           
    

二分查找

# 二分查找递归
int BinarySearchRecursion(int *arr, int value, int start, int end) {

    if (start > end || arr == NULL)
        return -1;

    int mid = (start + end) >> 1;

    if (arr[mid] == value) {

        return mid;

    } else if (value > arr[mid]) {

        return BinarySearchRecursion(arr, value,  mid + 1, end);

    } else {

        return BinarySearchRecursion(arr, value, start, mid - 1);

    }
}

# 二分查找
int BinarySearch(int arr[], int len, int value) {

    if (arr == NULL || len < 1)
        return -1;

    int start = 0;
    int end = len - 1;

    while (start < end) {

        int mid = (start + end) >> 1;

        if (arr[mid] == value)
            return mid;

        else if (arr[mid] > value)
            end = mid - 1;

        else
            start = mid + 1;
    }

    return -2;
}

冒泡排序

# 冒泡排序
void BubbleSort(int *arr, int len) {

    bool flag = true;
    int length = len;

    while(flag){
        flag = false;
        for (int i = 1; i < length; ++i) {
            if(arr[i-1]>arr[i]){
                swap(arr[i-1], arr[i]);
                flag = true;
            }
        }
        --length;
    }
}

归并算法

void MergeSort(int array[], int TempArray[], int left, int right) {

    if (right > left) {
        int middle = (left + right) >>1;
        MergeSort(array, TempArray, left, middle);
        MergeSort(array, TempArray, middle + 1, right);
        Merge(array, TempArray, left, middle, right);
    }
}

void MergeArray(int array[], int TempArray[], int left, int middle, int right) {

    int first = left;
    int end = right;
    int mid = middle;
    int mid_right = middle + 1;
    int key = 0;

    while (first <= mid && mid_right <= end) {

        if (array[first] < array[mid_right]) {
            TempArray[key++] = array[first++];
        } else {
            TempArray[key++] = array[mid_right++];
        }
    }

    while (first <= mid) {
        TempArray[key++] = array[first++];
    }

    while (mid_right <= end) {
        TempArray[key++] = array[mid_right++];
    }

    for (int i = 0; i < key; ++i) {
        array[left + i] = TempArray[i];
    }
}

void mergeSort(int array[]){

    int length = sizeof(array) / sizeof(int);
    int temp[length];
    MergeSort(array, temp, 0, length-1);
}

选择排序

# 选择排序
void SelectSort(int a[], int len) {

    int temp;
    int nIndex;

    for (int i = 0; i < len - 1; i++) {
        nIndex = i;

        for (int j = i + 1; j < len; j++) {
            if (a[j] < a[nIndex])
                nIndex = j;
        }

        if (nIndex != i) {
            temp = a[i];
            a[i] = a[nIndex];
            a[nIndex] = temp;
        }
    }
}

插入排序

# 插入排序
void InsertSort(int arr[], int len) {
    for (int i = 1; i < len; i++) {
        int key = arr[i];
        int j = i - 1;

        while (j >= 0 && arr[j] > key) {
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = key;
    }
}

Shell排序

# Shell排序
void ShellSort(int *number, int len) {
    int gap = len >> 1;

    while (gap > 0) {
        for (int k = 0; k < gap; k++) {
            for (int i = k + gap; i < len; i += gap) {
                for (int j = i - gap; j >= k; j -= gap) {
                    if (number[j] > number[j + gap])
                        swap(number[j], number[j + gap]);
                    else
                        break;
                }
            }
        }
        gap >>= 2;
    }
}