add Power of 2 file

Bitmasking/Powerof2.txt

@@ -0,0 +1,2 @@
+def isPowerOfTwo(self, n):
+    return (n>0) and (n & (n-1))==0

Graph/dijkstra.cpp

@@ -0,0 +1,106 @@
+// Author : GUNJAN KUMAR BISWAS
+#include<bits/stdc++.h>
+#define int long long
+using namespace std;
+void input_file()
+{
+#ifndef ONLINE_JUDGE
+    freopen("input.txt", "r", stdin);
+    freopen("output.txt", "w", stdout);
+#endif
+}
+
+#define all(v) v.begin() , v.end()
+#define int long long
+#define pb push_back
+#define ff first
+#define ss second
+
+const int N = (int)( 2e5 + 10);
+const int inf = (int)(1e18 + 10);
+#define P pair<int,int>
+
+map< P , int > mpp;
+vector<int>dist;
+vector<int>parent;
+vector<int>adj[N];
+
+void dijkstra()
+{
+    priority_queue< P , vector<P> , greater<P>> pq;
+    pq.push({0, 1});
+    // parent[1] = 0;
+    while (!pq.empty())
+    {
+        auto i = pq.top();
+        pq.pop();
+        int distance = i.ff;
+        int node = i.ss;
+
+        for (auto it : adj[node])
+        {
+            if (distance + mpp[ {node, it}] < dist[it])
+            {
+                dist[it] = distance + mpp[ {node, it}];
+                parent[it] = node ;
+                pq.push({dist[it] , it});
+            }
+        }
+    }
+
+}
+
+signed main()
+{
+    input_file();
+
+    int n, m;
+    cin >> n >> m;
+    dist = vector<int>(n + 10);
+    parent = vector<int>(n + 10);
+    for (int i = 1; i <= n; i++)
+    {
+        dist[i] = inf;
+        parent[i] = i;
+    }
+    dist[1] = 0;
+    for (int i = 1; i <= m; i++)
+    {
+        int u, v, w;
+        cin >> u >> v >> w;
+        mpp[ {u, v } ] = w;
+        mpp[ {v, u }]  = w;
+        adj[v].pb(u);
+        adj[u].pb(v);
+    }
+
+    dijkstra();
+    /*for(auto it : mpp)
+    {
+        cout << it.ff.ff <<" "<< it.ff.ss << " ="<<it.ss<<endl;
+    }*/
+    vector<int>ans;
+    ans.pb(n);
+    int ele = n;
+    /*for(auto it :parent)
+        cout << it<<" ";
+     */
+    if (dist[ele] == inf)   // disconnected graph
+    {
+        cout << -1 << endl;
+        return 0;
+    }
+    while (ele != 1)
+    {
+
+        ele = parent[ele];
+        ans.pb(ele);
+    }
+
+    reverse(all(ans));
+    for (auto it : ans)
+        cout << it << " ";
+    cout << endl;
+
+    return 0;
+}