Add prims algorithm and magic square implementation

graph/prims.cpp

@@ -0,0 +1,65 @@
+#include <bits/stdc++.h>
+using namespace std;
+/*
+    LOGIC
+    1.) Maintain two sets
+        i.)  First set contains vertices already included in MST
+        ii.) Second set contains vertices not yet included.
+    
+    2.) At every step consider all edges that connects two sets
+        pick the minm weight edge from these edges.
+
+
+*/
+int main()
+{
+    int N, m;
+    cin >> N >> m;
+    vector<pair<int, int>> adj[N];
+    int a, b, wt;
+    for (int i = 0; i < m; i++)
+    {
+        cin >> a >> b >> wt;
+        adj[a].push_back({b, wt});
+        adj[b].push_back({a, wt});
+    }
+    int parent[N];
+    int key[N];
+    bool mstSet[N];
+
+    for (int i = 0; i < N; i++)
+    {
+        key[i] = INT_MAX, mstSet[i] = false;
+    }
+    key[0] = 0;
+    parent[0] = -1;
+    int cost = 0;
+    for (int i = 0; i < N - 1; i++)
+    {
+        int minI = INT_MAX, u;
+        for (int v = 0; v < N; v++)
+        {
+            if (mstSet[v] == false && key[v] < minI)
+            {
+                minI = key[v], u = v;
+            }
+        }
+        mstSet[u] = true;
+        cost += minI;
+        for (auto it : adj[u])
+        {
+            int v = it.first;
+            int weight = it.second;
+            if (mstSet[v] == false && weight < key[v])
+            {
+                parent[v] = u, key[v] = weight;
+            }
+        }
+    }
+    cout << cost << endl;
+    for (int i = 1; i < N; i++)
+    {
+        cout << parent[i] << " " << i << "\n";
+    }
+    return 0;
+}

rbtr/magicSquare.py

@@ -0,0 +1,6 @@
+
+
+n = 3
+s = (n*((n**2) + 1))/2
+ans = [[0 for i in range(3)] for i in range(3)]
+used = [i for i in range(1, n**2 + 1)]