Added Binary Search in Infinite Length Array

BinarySearchInInfiniteLengthArray.java

@@ -0,0 +1,37 @@
+public class InfiniteLengthArray {
+    public static void main(String[] args) {
+        int[] arr = {3, 5, 7, 9, 10, 90,100, 130, 140, 160, 170};
+        int target = 100;
+        System.out.println(ans(arr, target));
+    }
+
+    static int ans(int[] arr, int target) {
+        // first find the range
+        // first start with the box of length 2
+        int start = 0;
+        int end = 1;
+        while(target > arr[end]) {
+            int temp = end + 1; // new start
+            // end = endPrevious + size*2;
+            end = end + (end - start + 1);
+            start = temp;
+        }
+        return BinarySearch(arr, target, start, end);
+    }
+
+    static int BinarySearch(int[] arr, int target, int start, int end) {
+        start = start;
+        end = end;
+        while (start < end){
+            int mid = start + (end - start)/2;
+            if (target < arr[mid]){
+                end = mid - 1;
+            } else if (target > arr[mid]) {
+                start = mid + 1;
+            }else {
+                return mid;
+            }
+        }
+        return -1;
+    }
+}