solved on 10/10/23

Author: Priyanshu-Ganatra

FindEvenNumbersInAnArrayUsingRecursion.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+void findEvenNumbers(int arr[], int n, int index, vector<int> &evens)
+{
+    if (index >= n)
+    {
+        return;
+    }
+    if (!(arr[index] & 1))
+    {
+        evens.push_back(arr[index]);
+    }
+    findEvenNumbers(arr, n, index + 1, evens);
+}
+
+int main()
+{
+    int arr[] = {1, 2, 3, 4, 5};
+    int n = 5;
+    vector<int> evens;
+    findEvenNumbers(arr, n, 0, evens);
+    cout << "Even numbers in the array are: ";
+    for (int i = 0; i < evens.size(); i++)
+    {
+        cout << evens[i] << " ";
+    }
+    cout << endl;
+    return 0;
+}

LC_53_ClimbingStairs.cpp

@@ -0,0 +1,35 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+// can either take 1 step or 2 steps at a time to reach the top of the stairs (n)
+int climbStairs(int n)
+{
+    // TLE
+    // if(n == 2){
+    //     return 2;
+    // }
+    // if(n == 1){
+    //     return 1;
+    // }
+    // int ans = climbStairs(n-1) + climbStairs(n-2);
+    // return ans;
+
+    // Brute
+    int prev1 = 0;
+    int prev2 = 1;
+    for (int i = 0; i <= n - 2; i++)
+    {
+        int temp = prev1 + prev2;
+        prev1 = prev2;
+        prev2 = temp;
+    }
+    return prev1 + prev2;
+}
+
+int main()
+{
+    int n;
+    cin >> n;
+    cout << climbStairs(n) << endl;
+    return 0;
+}

MinimumNumberInArrayUsingRecursion.cpp

@@ -0,0 +1,26 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+void findMin(int arr[], int n, int index, int &min)
+{
+    if (index >= n)
+    {
+        return;
+    }
+    if (arr[index] < min)
+    {
+        min = arr[index];
+    }
+    findMin(arr, n, index + 1, min);
+}
+
+int main()
+{
+    int arr[] = {1, 2, 3, 4, 5};
+    int n = 5;
+    int min = INT_MAX;
+    findMin(arr, n, 0, min);
+    cout << "Minimum element in the array is: ";
+    cout << min << endl;
+    return 0;
+}

PrintArrayUsingRecursion.cpp

@@ -0,0 +1,19 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+void printArray(vector<int> &nums, int idx)
+{
+    if (idx == nums.size())
+    {
+        return;
+    }
+    cout << nums[idx] << " ";
+    printArray(nums, idx + 1);
+}
+
+int main()
+{
+    vector<int> nums = {1, 2, 3, 4, 5};
+    printArray(nums, 0);
+    return 0;
+}

SearchInArrayUsingRecursion.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int search(int arr[], int n, int key, int index)
+{
+    if (index == n)
+    {
+        return -1;
+    }
+    if (arr[index] == key)
+    {
+        return index;
+    }
+    return search(arr, n, key, index + 1);
+}
+
+int main()
+{
+    int arr[] = {1, 2, 3, 4, 5};
+    int n = 5;
+    int key = 3;
+    cout << key << " found at index: ";
+    cout << search(arr, n, key, 0) << endl;
+    return 0;
+}