题解 | 最大乘积

import sys


def main():

    n = int(sys.stdin.readline())
    A = list(map(int, sys.stdin.readline().strip().split()))

    max1 = max2 = max3 = float("-inf")  # max1>=max2>=max3
    min1 = min2 = float("inf")  # min1<=min2

    for a in A:
        if a > max1:
            max3 = max2
            max2 = max1
            max1 = a
            
        elif a > max2:
            max3 = max2
            max2 = a
            
        elif a > max3:
            max3 = a
        
        if a<min1:
            min2 = min1
            min1 = a
            
        elif a<min2:
            min2 = a
    
    print(max(max1*max2*max3, min1*min2*max1))


if __name__ == "__main__":
    main()