piyush121 - 8 months ago 28

Java Question

I am trying to calculate an expression in java which is in String

i.e

`99999999999999999^99999999999999999`

I want to calculate this number modulo

`1000000007`

I currently trying to store the big numbers as double but taking modulo with double gives me

`NaN`

Can somebody help ?

Answer

You can use `BigInteger`

and `modPow(BigInteger, BigInteger)`

like

```
BigInteger m = new BigInteger("1000000007");
BigInteger a = new BigInteger("99999999999999999");
BigInteger b = new BigInteger("99999999999999999");
BigInteger answer = a.modPow(b, m);
System.out.println(answer);
```

which gives

```
265859324
```

Source (Stackoverflow)