题解 | 大整数相乘

import sys

nine_nine = []
for i in range(0, 10):
    line = []
    for j in range(0, 10):
        line.append(i * j)
    nine_nine.append(line)

def add(a1, b1):
    def add_(a, b):
        out = []
        upper = 0
        for k, i in enumerate(a):
            if k < len(b):
                re = i + b[k] + upper
            else:
                re = i + upper
            upper = re // 10
            out.append(re % 10)
        if upper != 0:
            out.append(upper)
        return out

    if len(a1) > len(b1):
        return add_(a1, b1)
    else:
        return add_(b1, a1)


def solve(a:str, b:str):
    outs = []
    last = []
    this = []
    result = []
    for k, i in enumerate(a[::-1]):
        upper = 0
        this = [0 for _ in range(k)]
        for j in b[::-1]:
            r = int(i) * int(j) + upper
            re = r % 10
            this.append(re)
            upper = r // 10
        if upper != 0:
            this.append(upper)
        outs.append(this)

        if last != []:
            result = add(last, this)
            # print(f"{last}+{this}={result}")
        else: 
            result = this
        last = result
    # print(outs)
    return result


for line in sys.stdin:
    a,b = line.split()
    aws = solve(a, b)
    for i in aws[::-1]:
        print(i, end="")
    print()

纯纯的牛马题，用手算的思路来解