codernoob1
diff --git a/‎lectures/14-recursion/Recursion - Arrays.pdf‎
1.54 MB b/‎lectures/14-recursion/Recursion - Arrays.pdf‎
1.54 MB
diff --git a/‎lectures/14-recursion/code/src/com/kunal/arrays/Find.java‎
Lines changed: 94 additions & 0 deletions b/‎lectures/14-recursion/code/src/com/kunal/arrays/Find.java‎
Lines changed: 94 additions & 0 deletions
diff --git a/‎lectures/14-recursion/code/src/com/kunal/arrays/RBS.java‎
Lines changed: 34 additions & 0 deletions b/‎lectures/14-recursion/code/src/com/kunal/arrays/RBS.java‎
Lines changed: 34 additions & 0 deletions
diff --git a/‎lectures/14-recursion/code/src/com/kunal/arrays/Sorted.java‎
Lines changed: 17 additions & 0 deletions b/‎lectures/14-recursion/code/src/com/kunal/arrays/Sorted.java‎
Lines changed: 17 additions & 0 deletions
@@ -0,0 +1,94 @@
+package com.kunal.arrays;
+
+import java.util.ArrayList;
+
+public class Find {
+    public static void main(String[] args) {
+        int[] arr = {2, 3, 1, 4, 4, 5};
+//        System.out.println(find(arr, 4, 0));
+//        System.out.println(findIndex(arr, 4, 0));
+//        System.out.println(findIndexLast(arr, 4, arr.length-1));
+//        findAllIndex(arr, 4, 0);
+//        System.out.println(list);
+
+//        ArrayList<Integer> list = new ArrayList<>();
+//        ArrayList<Integer> ans = findAllIndex(arr, 4, 0, list);
+//        System.out.println(ans);
+//        System.out.println(list);
+
+        System.out.println(findAllIndex2(arr, 4, 0));
+
+
+    }
+
+    static boolean find(int[] arr, int target, int index) {
+        if (index == arr.length) {
+            return false;
+        }
+        return arr[index] == target || find(arr, target, index + 1);
+    }
+
+    static int findIndex(int[] arr, int target, int index) {
+        if (index == arr.length) {
+            return -1;
+        }
+        if (arr[index] == target) {
+            return index;
+        } else {
+            return findIndex(arr, target, index + 1);
+        }
+    }
+
+    static int findIndexLast(int[] arr, int target, int index) {
+        if (index == -1) {
+            return -1;
+        }
+        if (arr[index] == target) {
+            return index;
+        } else {
+            return findIndexLast(arr, target, index - 1);
+        }
+    }
+
+    static ArrayList<Integer> list = new ArrayList<>();
+    static void findAllIndex(int[] arr, int target, int index) {
+        if (index == arr.length) {
+            return;
+        }
+        if (arr[index] == target) {
+            list.add(index);
+        }
+        findAllIndex(arr, target, index + 1);
+    }
+
+    static ArrayList<Integer> findAllIndex(int[] arr, int target, int index, ArrayList<Integer> list) {
+        if (index == arr.length) {
+            return list;
+        }
+        if (arr[index] == target) {
+            list.add(index);
+        }
+        return findAllIndex(arr, target, index + 1, list);
+    }
+
+    static ArrayList<Integer> findAllIndex2(int[] arr, int target, int index) {
+
+        ArrayList<Integer> list = new ArrayList<>();
+
+        if (index == arr.length) {
+            return list;
+        }
+
+        // this will contain answer for that function call only
+        if (arr[index] == target) {
+            list.add(index);
+        }
+        ArrayList<Integer> ansFromBelowCalls = findAllIndex2(arr, target, index + 1);
+
+        list.addAll(ansFromBelowCalls);
+
+        return list;
+    }
+
+
+}
@@ -0,0 +1,34 @@
+package com.kunal.arrays;
+
+public class RBS {
+    public static void main(String[] args) {
+        int[] arr = {5, 6, 7, 8, 9, 1, 2, 3};
+        System.out.println(search(arr, 4, 0, arr.length - 1));
+    }
+
+    static int search(int[] arr, int target, int s, int e) {
+        if (s > e) {
+            return -1;
+        }
+
+        int m = s + (e-s) / 2;
+        if (arr[m] == target) {
+            return m;
+        }
+
+        if (arr[s] <= arr[m]) {
+            if (target >= arr[s] && target <= arr[m]) {
+                return search(arr, target, s, m-1);
+            } else {
+                return search(arr, target, m+1, e);
+            }
+        }
+
+        if (target >= arr[m] && target <= arr[e]) {
+            return search(arr, target, m+1, e);
+        }
+
+        return search(arr, target, s, m-1);
+    }
+
+}
@@ -0,0 +1,17 @@
+package com.kunal.arrays;
+
+public class Sorted {
+    public static void main(String[] args) {
+        int[] arr = {1, 2, 3, 5, 16, 8};
+        System.out.println(sorted(arr, 0));
+    }
+
+    static boolean sorted(int[] arr, int index) {
+        // base condition
+        if (index == arr.length - 1) {
+            return true;
+        }
+
+        return arr[index] < arr[index + 1] && sorted(arr, index + 1);
+    }
+}