From eeb229e6cf8ba52c9a8d7461ba44d9d466d83d80 Mon Sep 17 00:00:00 2001
From: Rohan Dable <90612195+RohanDable@users.noreply.github.com>
Date: Mon, 30 Oct 2023 22:05:36 +0530
Subject: [PATCH] added

---
 C++/Topological_sort.cpp | 82 +++++++++++++++++++++++++++++++++++++
 C++/Tower_Of_Hanoi.cpp   | 22 ++++++++++
 Selection Sort           | 87 ++++++++++++++++++----------------------
 3 files changed, 143 insertions(+), 48 deletions(-)
 create mode 100644 C++/Topological_sort.cpp
 create mode 100644 C++/Tower_Of_Hanoi.cpp

diff --git a/C++/Topological_sort.cpp b/C++/Topological_sort.cpp
new file mode 100644
index 000000000..e83d4d1a2
--- /dev/null
+++ b/C++/Topological_sort.cpp
@@ -0,0 +1,82 @@
+// C++ Program for topological sort using BFS
+
+#include <bits/stdc++.h>
+using namespace std;
+
+bool topological_sort(int n, vector<int> adj[], vector<int> ans)
+{
+
+    vector<int> indegree(n, 0);
+
+    for (int i = 0; i < adj.size(); i++)
+        indegree[adj[i][1]]++;
+
+    queue<int> q;
+
+    for (int i = 0; i < n; i++)
+    {
+        if (indegree[i] == 0)
+            q.push(i);
+    }
+
+    if (!q.empty())
+        return false;
+
+    while (!q.empty())
+    {
+
+        int node = q.front();
+        q.pop();
+
+        ans.push_back(node);
+
+        for (auto it : adj[node])
+        {
+
+            indegree[it]--;
+
+            if (indegree[it] == 0)
+                q.push(it);
+        }
+    }
+
+    for (int i = 0; i < n; i++)
+    {
+        if (indegree[i] != 0)
+            return false;
+    }
+
+    return true;
+}
+
+// Driver program to check above functions
+int main()
+{
+    int n, e; // Input for no. of nodes and edges
+    cin >> n >> e;
+
+    vector<int> adj[n];
+    int u, v;
+
+    for (int i = 0; i < e; i++)
+    {
+        cin >> u >> v;
+
+        adj[u].push_back(v);
+    }
+
+    vector<int> ans;
+
+    bool check = topological_sort(n, adj, ans); // Calling function for topological sort
+
+    if (check == false)
+        cout << "Not Possible\n";
+    else
+    {
+        for (auto it : ans)
+            cout << it << " ";
+    }
+    cout << endl;
+
+    return 0;
+}
diff --git a/C++/Tower_Of_Hanoi.cpp b/C++/Tower_Of_Hanoi.cpp
new file mode 100644
index 000000000..2eee096e1
--- /dev/null
+++ b/C++/Tower_Of_Hanoi.cpp
@@ -0,0 +1,22 @@
+#include <iostream>
+using namespace std;
+void toh(int n, char s, char h, char d)
+{
+    if (n == 1)
+    {
+        cout << "Move disk " << n << " from rod " << s << " to rod " << d << endl;
+        return;
+    }
+    toh(n - 1, s, d, h);
+    cout << "Move disk " << n << " from rod " << s << " to rod " << d << endl;
+    toh(n - 1, h, s, d);
+}
+
+int main()
+{
+    cout << "enter number of disks = " << endl;
+    int n;
+    cin >> n;
+    toh(n, 'A', 'B', 'C');
+    return 0;
+}
diff --git a/Selection Sort b/Selection Sort
index 74c560ebc..b6ef61871 100644
--- a/Selection Sort	
+++ b/Selection Sort	
@@ -1,48 +1,39 @@
-#include <bits/stdc++.h> 
-using namespace std; 
-  
-void swap(int *xp, int *yp)  
-{  
-    int temp = *xp;  
-    *xp = *yp;  
-    *yp = temp;  
-}  
-  
-void selectionSort(int arr[], int n)  
-{  
-    int i, j, min_idx;  
-  
-    // One by one move boundary of unsorted subarray  
-    for (i = 0; i < n-1; i++)  
-    {  
-        // Find the minimum element in unsorted array  
-        min_idx = i;  
-        for (j = i+1; j < n; j++)  
-        if (arr[j] < arr[min_idx])  
-            min_idx = j;  
-  
-        // Swap the found minimum element with the first element  
-        swap(&arr[min_idx], &arr[i]);  
-    }  
-}  
-  
-/* Function to print an array */
-void printArray(int arr[], int size)  
-{  
-    int i;  
-    for (i=0; i < size; i++)  
-        cout << arr[i] << " ";  
-    cout << endl;  
-}  
-  
-// Driver program to test above functions  
-int main()  
-{  
-    int arr[] = {64, 25, 12, 22, 11};  
-    int n = sizeof(arr)/sizeof(arr[0]);  
-    selectionSort(arr, n);  
-    cout << "Sorted array: \n";  
-    printArray(arr, n);  
-    return 0;  
-}  
-  
+#include<iostream>
+using namespace std;
+void swapping(int &a, int &b) {         //swap the content of a and b
+   int temp;
+   temp = a;
+   a = b;
+   b = temp;
+}
+void display(int *array, int size) {
+   for(int i = 0; i<size; i++)
+      cout << array[i] << " ";
+   cout << endl;
+}
+void selectionSort(int *array, int size) {
+   int i, j, imin;
+   for(i = 0; i<size-1; i++) {
+      imin = i;   //get index of minimum data
+      for(j = i+1; j<size; j++)
+         if(array[j] < array[imin])
+            imin = j;
+         //placing in correct position
+         swap(array[i], array[imin]);
+   }
+}
+int main() {
+   int n;
+   cout << "Enter the number of elements: ";
+   cin >> n;
+   int arr[n];           //create an array with given number of elements
+   cout << "Enter elements:" << endl;
+   for(int i = 0; i<n; i++) {
+      cin >> arr[i];
+   }
+   cout << "Array before Sorting: ";
+   display(arr, n);
+   selectionSort(arr, n);
+   cout << "Array after Sorting: ";
+   display(arr, n);
+}