43. Multiply Strings_v2.py

class Solution:
    def multiply(self, num1: str, num2: str) -> str:
        if num1=="0" or num2=="0":
            return "0"
        #print(num1[::-1])
        n1 = []
        n2 = []
        ans = []
        for i in num1[::-1]:
            n1.append(int(i))
        for j in num2[::-1]:
            n2.append(int(j))
        #print(n1," ",n2)    
        maX=max(len(n1),len(n2))
        #print("maX:",maX)
        
        diff = abs(len(n1)-len(n2))
        #print(diff)
        if len(n1)>len(n2):
            for k1 in range(diff):
                n2.append(0)
        else:
            for k2 in range(diff):
                n1.append(0)
        #print(n1,n2)        
        #print(len(n1),len(n2))
        for c in range(len(n1)*2):
            ans.append(0)
        #print("ans:",ans)    
        for a in range(len(n1)):
            for b in range(len(n2)):
                #print(a,"-",b)
                ans[a+b] += n1[a]*n2[b] #
                if ans[a+b] >= 10:
                    ans[a+b+1] += int((ans[a+b]/10))
                    ans[a+b] = int(ans[a+b]%10)                 
        #print(ans)
        '''
        ans.reverse()
        print(ans)
        ans_str = ""
        for an in ans:
        ''' 
        print("ans:",ans)
        ans_str = ""
        head=0
        for z in range(len(ans)-1,-1,-1):
            if ans[z]!=0 or head==1:
                ans_str+=str(ans[z])
                head=1
        #print(ans_str)
        return ans_str