From 04d750c85f23ae2b6da85531961f186176b529ca Mon Sep 17 00:00:00 2001
From: Sai Lalitha Sunaina Madgula <sunaina7571@gmail.com>
Date: Tue, 14 Oct 2025 17:25:53 -0400
Subject: [PATCH] Binary-search-1

---
 2DMatrix.java           | 30 ++++++++++++++++++++++++++++++
 RotatedSortedArray.java | 33 +++++++++++++++++++++++++++++++++
 UnkownSortedArray.java  | 28 ++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 2DMatrix.java
 create mode 100644 RotatedSortedArray.java
 create mode 100644 UnkownSortedArray.java

diff --git a/2DMatrix.java b/2DMatrix.java
new file mode 100644
index 00000000..c0772e84
--- /dev/null
+++ b/2DMatrix.java
@@ -0,0 +1,30 @@
+class Solution {
+    public boolean searchMatrix(int[][] matrix, int target) {
+        if(matrix == null || matrix.length ==0){
+            return false;
+        }
+        int m = matrix.length;
+        int n = matrix[0].length;
+        int low = 0;
+        int high = m*n - 1;
+
+        while(low<=high){
+            int mid = low + (high-low)/2;
+            int r = mid/n;
+            int c = mid % n;
+            if(matrix[r][c] == target){
+                return true;
+            }
+            else if(matrix[r][c] < target){
+                low = mid + 1;
+
+            }
+            else{
+                high = mid - 1;
+            }
+        }
+        
+        return false;
+    }
+    
+}
\ No newline at end of file
diff --git a/RotatedSortedArray.java b/RotatedSortedArray.java
new file mode 100644
index 00000000..05bb6bf6
--- /dev/null
+++ b/RotatedSortedArray.java
@@ -0,0 +1,33 @@
+class Solution {
+    public int search(int[] nums, int target) {
+        int low = 0;
+        int high =  nums.length-1;
+
+        while(low <= high){
+            int mid = low + (high-low)/2;
+            if(nums[mid] == target){
+                return mid;
+            }
+            
+            else if(nums[low] <= nums[mid]){
+                if(nums[low]<=target && target<nums[mid]){
+                    high=mid-1;
+
+                }
+                else{
+                    low = mid+1;
+                }
+               
+            }
+            else{
+                if(nums[mid]<target && target <=nums[high]){
+                    low = mid+1;
+                }
+                else{
+                    high = mid -1;
+                }
+            }
+        }
+        return -1;
+    }
+}
\ No newline at end of file
diff --git a/UnkownSortedArray.java b/UnkownSortedArray.java
new file mode 100644
index 00000000..1a59106c
--- /dev/null
+++ b/UnkownSortedArray.java
@@ -0,0 +1,28 @@
+class Solution {
+    public int search(ArrayReader reader, int target) {
+        int low = 0;
+        int high = 1;
+
+        // Expand the search window exponentially
+        while (reader.get(high) < target) {
+            low = high;
+            high = high * 2;
+        }
+
+        // Binary search
+        while (low <= high) {
+            int mid = low + (high - low) / 2;
+            int val = reader.get(mid);
+
+            if (val == target) {
+                return mid; // ✅ found
+            } else if (val > target) {
+                high = mid - 1;
+            } else {
+                low = mid + 1;
+            }
+        }
+
+        return -1; // not found
+    }
+}