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MultiplyStrings.java
29 lines (28 loc) · 1018 Bytes
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MultiplyStrings.java
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public class MultiplyStrings{
public String multiply(String num1, String num2) {
if(num1 == null || num2 == null || num1.length() == 0 || num2.length() == 0)
return "";
int[] result = new int[num1.length() + num2.length()];
for(int i = 0; i < num1.length(); i++){
for(int j = 0; j < num2.length(); j++){
result[i+j+1] += (num1.charAt(i) - '0') * (num2.charAt(j) - '0');
}
}
for(int i = result.length - 1; i > 0; i--){
result[i-1] += result[i] / 10;
result[i] = result[i] % 10;
}
StringBuilder sb = new StringBuilder();
boolean nonzero = false;
for(int i = 0; i < result.length - 1; i++){
if(result[i] != 0){
nonzero = true;
sb.append(result[i]);
} else if(nonzero){
sb.append(result[i]);
}
}
sb.append(result[result.length-1]);
return sb.toString();
}
}