BOJ#13706 제곱근

BOJ#13706 제곱근

* 문제

https://www.acmicpc.net/problem/13706

* 풀이

이분 탐색, BigInteger 사용

* 나의 코드

https://github.com/stack07142/BOJ/blob/bcbfa3899c5c3acae75e515c8642eddcb3a9067e/BOJ%2313706/src/Main.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;

public class Main {

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String num = br.readLine();

        sqrt(num);
    }

    static void sqrt(String num) {

        BigInteger one = BigInteger.ONE;
        BigInteger two = new BigInteger("2");

        BigInteger target = new BigInteger(num);

        BigInteger left = BigInteger.ONE;
        BigInteger right = new BigInteger(num);

        BigInteger mid, x;

        while (left.compareTo(right) <= 0) {

            mid = (left.add(right)).divide(two);
            x = mid.multiply(mid);

            int ret = x.compareTo(target);
            if (ret == 0) {

                System.out.println(mid.toString());
                break;
            } else if (ret == -1) {

                left = mid.add(one);
            } else if (ret == 1) {

                right = mid.subtract(one);
            }
        }
    }
}