heap sort added

Dynamic Programming/LongestPalindromicSubsequence-DP.cpp

@@ -0,0 +1,47 @@
+// Author : Ritik Patil
+// Date : 11/10/2022
+// Time : 23:19
+// Description : Added Famous OA round question with help of DP
+/*Given A string, find the length of longest palindrome present in the string .*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+/* Returns length of longest Palindrome Subsequence for a string */
+int longestPalindromeSubsequence(string s)
+{
+    string t = s;
+    reverse(t.begin(), t.end());
+    int n = s.size();
+    vector<vector<int>> dp(n + 1, vector<int>(n + 1, 0));
+    for (int i = 0; i <= n; i++)
+    {
+        dp[i][0] = dp[0][i] = 0;
+    }
+    for (int i = 1; i <= n; i++)
+    {
+        for (int j = 1; j <= n; j++)
+        {
+            if (s[i - 1] == t[j - 1])
+            {
+                dp[i][j] = 1 + dp[i - 1][j - 1];
+            }
+            else
+            {
+                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
+            }
+        }
+    }
+    return dp[n][n];
+}
+
+int main()
+{
+    string s;
+    cout << "Enter your string : ";
+    cin >> s;
+
+    cout << "Length of Longest Palindrome Subsequence is : " << longestPalindromeSubsequence(s);
+
+    return 0;
+}

sorting/heapSort.cpp

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+// C++ program for implementation of Heap Sort
+#include <iostream>
+using namespace std;
+
+// To heapify a subtree rooted with node i which is
+// an index in arr[]. n is size of heap
+void heapify(int arr[], int n, int i)
+{
+	int largest = i; // Initialize largest as root
+	int l = 2 * i + 1; // left = 2*i + 1
+	int r = 2 * i + 2; // right = 2*i + 2
+
+	// If left child is larger than root
+	if (l < n && arr[l] > arr[largest])
+		largest = l;
+
+	// If right child is larger than largest so far
+	if (r < n && arr[r] > arr[largest])
+		largest = r;
+
+	// If largest is not root
+	if (largest != i) {
+		swap(arr[i], arr[largest]);
+
+		// Recursively heapify the affected sub-tree
+		heapify(arr, n, largest);
+	}
+}
+
+// main function to do heap sort
+void heapSort(int arr[], int n)
+{
+	// Build heap (rearrange array)
+	for (int i = n / 2 - 1; i >= 0; i--)
+		heapify(arr, n, i);
+
+	// One by one extract an element from heap
+	for (int i = n - 1; i >= 0; i--) {
+		// Move current root to end
+		swap(arr[0], arr[i]);
+
+		// call max heapify on the reduced heap
+		heapify(arr, i, 0);
+	}
+}
+
+/* A utility function to print array of size n */
+void printArray(int arr[], int n)
+{
+	for (int i = 0; i < n; ++i)
+		cout << arr[i] << " ";
+	cout << "\n";
+}
+
+// Driver program
+int main()
+{
+	int arr[] = { 12, 11, 13, 5, 6, 7 };
+	int n = sizeof(arr) / sizeof(arr[0]);
+
+	heapSort(arr, n);
+
+	cout << "Sorted array is \n";
+	printArray(arr, n);
+}