quickSort

今天闲来无事，复习了一下快排

首先写了一个partition

int partition(int __toSort[], int __low, int __high) {
    int pivokey__ = __toSort[__low];
    while(__low < __high) {
        
        while(__low < __high && __toSort[__high] >= pivokey__) {
            __high--;
        }
        swap(__toSort, __low, __high);
        
        
        while(__low < __high && __toSort[__low] <= pivokey__) {
            __low++;
        }
        swap(__toSort, __low, __high);
        
    }

    return __low;
}

再写quickSort()

void quickSort(int __toSort[], int __low, int __high) {
    
    int midium__ = partition2(__toSort, __low, __high);
    quickSort(__toSort, __low, midium__ -1);
    quickSort(__toSort, midium__ +1, __high);
        
}

运行，怎么运行错误？

开始怀疑是Partition()写错了，后来发现忘记写递归退出条件了，悲哀！

改过来

void quickSort(int __toSort[], int __low, int __high) {
    if(__low < __high) {
        int midium__ = partition2(__toSort, __low, __high);
    quickSort(__toSort, __low, midium__ -1);
    quickSort(__toSort, midium__ +1, __high);
    }
    
}

运行成功。

之后将partition升级

int partition2(int __toSort[], int __low, int __high) {
    int pivokey__ = __toSort[__low];
    while(__low < __high) {
        
        while(__low < __high && __toSort[__high] >= pivokey__) {
            __high--;
        }
        __toSort[__low] = __toSort[__high];
        
        
        while(__low < __high && __toSort[__low] <= pivokey__) {
            __low++;
        }
        __toSort[__high] = __toSort[__low];
        
    }
    __toSort[__low] = pivokey__;

    return __low;
}

运行成功