Create 0069-sqrtx.java

Language used : java
Runtime : 1ms, faster than 100%
Submission : https://leetcode.com/problems/sqrtx/submissions/999842542/

Author: arychin

Diff for: java/0069-sqrtx.java

@@ -0,0 +1,29 @@
+class Solution {
+    public int mySqrt(int x) {
+        
+        // Linear search way -> loop through for all nums till x
+        // then see if their square <= x
+
+        // Binary Search way -> we can optimise our approach by observing
+        // that nums till x are sorted
+
+        int left = 0;
+        int right = x;
+        int mid = 0;
+        int probableAns = 0;
+
+        while(left <= right){
+            mid = left + (right-left)/2;
+            if((long)mid*mid <= (long)x){
+                probableAns = mid;
+                // let's see if we can find a bigger num
+                left = mid+1;
+            }
+            else if((long)mid*mid > (long)x){
+                right = mid-1;
+            }
+        }
+
+        return probableAns;
+    }
+}