finds square root of N without using inbuild library, 2 approaches

Author: NirmalSilwal

Leetcode/Youtube/SquareRootX.java

@@ -0,0 +1,63 @@
+package Leetcode.Youtube;
+
+public class SquareRootX {
+
+	public static int mySqrt(int x) {
+
+		for (int i = 0; i <= x; i++) {
+
+			if (i * i == x)
+				return i;
+
+			if (i * i > x) {
+				return i - 1;
+			}
+		}
+
+		return -1;
+	}
+
+	// optimal approach using binary search
+	public static int mySqrt2(int x) {
+		if (x < 2)
+			return x;
+
+		long low = 1, high = x / 2;
+		long ans = 0;
+
+		while (low <= high) {
+			
+			long mid = low + (high - low) / 2;
+
+			if (mid * mid <= x) {
+				ans = mid;
+				low = mid + 1;
+			} else {
+				high = mid - 1;
+			}
+		}
+
+		return (int)ans;
+	}
+
+	public static void main(String[] args) {
+
+		System.out.println(mySqrt(4));
+		System.out.println(mySqrt(8));
+		System.out.println(mySqrt(2));
+		System.out.println(mySqrt(67));
+		System.out.println(mySqrt(86));
+		System.out.println(mySqrt(40));
+		System.out.println(mySqrt(999999999));
+		
+		System.out.println();
+		
+		System.out.println(mySqrt2(4));
+		System.out.println(mySqrt2(8));
+		System.out.println(mySqrt2(2));
+		System.out.println(mySqrt2(67));
+		System.out.println(mySqrt2(86));
+		System.out.println(mySqrt2(40));
+		System.out.println(mySqrt2(999999999));
+	}
+}