public class Solution {

public String multiply(String num1, String num2) {

// Start typing your Java solution below

// DO NOT write main() function

if(num1.equals("0") || num2.equals("0")){

return "0";

}

int res[] = new int[num1.length()+num2.length()];

int l3 = num1.length()+num2.length()-1;

int l2 = num2.length()-1;

int l1 = num1.length()-1;

for(int i=0;i<num1.length();i++){

for(int j=0;j<num2.length();j++){

res[l3-i-j] += (num1.charAt(l1-i)-'0')*(num2.charAt(l2-j)-'0');

}

}

for(int i=0;i<l3;i++){

res[l3-i-1] += res[l3-i]/10;

res[l3-i] = res[l3-i]%10;

}

int ii=0;

while(res[ii]==0) ii++;

StringBuilder sb = new StringBuilder("");

for(;ii<=l3;ii++){

sb.append((char)(res[ii]+'0'));

}

return sb.toString();

}

}