最大配对乘积的Python

问题描述

n = int(input("Enter the number of elements in the array (2-200,000):"))
a = [int(x) for x in input("Enter all numbers of the sequence with only non-negative intergers not exceeding 100,000:").split()]
c = list()3

for i in range(0,n):
    for j in range (1,n):
        if a[i] != a[j]:
            m = a[i]*a[j]
            c.append(m)
        else:
            continue
print(max(c))

此代码可以工作。但是，我想定义一个函数来自动计算以下代码中第5行的最大乘积。

def MaxPairwiseProduct(n,a,c):
for i in range(0,n):
    for j in range (1,n):
        if a[i] != a[j]:
            m = a[i]*a[j]
            c.append(m)
        else:
            continue

        Product = max(c)

        return Product

n = int(input("Enter the number of elements in the array (2-200,000):"))
a = [int(x) for x in input("Enter all numbers of the sequence with only non-negative intergers not exceeding 100,000:").split()]
c = list()
MaxPairwiseProduct(n,a,c)

我重写了该函数，但它不起作用。它显示"IndentationError：预期为缩进块"

---

解决方案

# Uses python3
def MaxPairwiseProduct(n,a,c):
    for i in range(0,n):
        for j in range (1,n):
            if a[i] != a[j]:
                m = a[i]*a[j]
                c.append(m)

            else:
                continue

    Product1 = max(c)
    return Product1

def MaxPairwiseProductFast(n,a):
    max_index1 = -1
    for i in range(0,n):
        if a[i] > a[max_index1]:
            max_index1 = i
        else:
            continue
    #the value of the other index should be different compared to the        #first, else it will assume the same indices for both the max         
    max_index2 = -2
    for j in range(0,n):
        if a[j] > a[max_index2] and a[j] != a[max_index1]:
            max_index2 = j   
        else:
            continue

    Product2 = a[max_index1]*a[max_index2]
    return Product2

n = int(input("Enter the number of elements in the array (2-200,000):"))
a = [int(x) for x in input("Enter all numbers of the sequence with only non-negative intergers not exceeding 100,000:").split()]
c = list()

print('The max value by regular algorithm:', MaxPairwiseProduct(n,a,c))
print('The max value by faster algorithm:', MaxPairwiseProductFast(n,a))  

此代码包含计算最大值的第二种算法。