python实现各种排序算法

python排序算法

# -*-encoding: utf-8 -*-# param: a    a list which to be sortclass MultiSort(object):    # 交换函数    def exch(self, a, i, j):        temp = a[i]        a[i] = a[j]        a[j] = temp    # 插入排序    def insertionSort(self, a):        N = len(a)        if N == 1:            return a        for i in range(1, N):            for j in range(1, i + 1)[::-1]:                if a[j] < a[j - 1]:                    self.exch(a, j, j - 1)                    # print a        return a    # 选择排序    def selectionSort(self, a):        N = len(a)        if N == 1:            return a        for i in range(N):            mins = i            for j in range(i + 1, N):                if (a[mins] > a[j]):                    mins = j            self.exch(i, mins)            # print a        return a    # 希尔排序    def shellSort(self, a):        N = len(a)        h = 1        if N == 1:            return a        while h < (N // 3):            h = 3 * h + 1        while h >= 1:            for i in range(h, N):                for j in range(i, 0, -h):                    if j >= h:                        if a[j] < a[j - h]:                            self.exch(a, j, j - h)                            # print self.a                    j -= h            h //= 3        return a    # 归并排序：__merge与__mSort为辅助函数    def __merge(self, a, lo, mid, hi):        from copy import deepcopy        i = lo        j = mid + 1        aux = deepcopy(a)        for k in range(lo, hi + 1):            if i > mid:                a[k] = aux[j]                j += 1            elif j > hi:                a[k] = aux[i]                i += 1            elif aux[j] < aux[i]:                a[k] = aux[j]                j += 1            else:                a[k] = aux[i]                i += 1            print a    def __mSort(self, a, lo, hi):        if hi <= lo:            return        mid = lo + (hi - lo) // 2        self.__mSort(a, lo, mid)        self.__mSort(a, mid + 1, hi)        self.__merge(a, lo, mid, hi)    def mergeSort(self, a):        self.__mSort(a, 0, len(a) - 1)        return a    # 快速排序：辅助函数__partition和__qSort    def __partition(self, a, lo, hi):        i = lo        j = hi + 1        v = a[lo]        while True:            while True:                i += 1                if a[i] < v:                    if i == hi:                        break                else: break            while True:                j -= 1                if v < a[j]:                    if j == lo:                        break                else: break            if i >= j: break            self.exch(a, i, j)        self.exch(a, lo, j)        return j    def __qSort(self, a, lo, hi):        if hi <= lo: return        j = self.__partition(a, lo, hi)        self.__qSort(a, lo, j-1)        self.__qSort(a, j+1, hi)    def quickSort(self, a):        import random        random.shuffle(a)        self.__qSort(a, 0, len(a)-1)        return a# 冒泡排序    def bubbleSort(self, a):        length = len(a)        for i in range(length-1):            # print "第%d趟:" % (i+1)            isSorted = True            for j in range(length-1-i):                if a[j] > a[j+1]:                    self.exch(a, j, j+1)                    isSorted = False                # print "第%d次:" % (j + 1), a            if isSorted:                break        return aif __name__ == "__main__":    import numpy as np    # a = np.random.randint(1, 100000, size=100, dtype=np.int64)    a = [49, 38, 65, 97, 26, 13, 27, 49, 55, 4]    # print a    b = MultiSort()    # b.insertionSort(a)    # b.selectionSort(a)    # b.shellSort(a)    print "========================"    print b.bubbleSort(a)    print "========================"