Kruskal Algorithm.cpp

C++/Kosaraju's algorithm.cpp

@@ -0,0 +1,98 @@
+//Name-Avnish Kumar
+//Github id-Avnish010
+#include <bits/stdc++.h>
+using namespace std;
+typedef long long int ll;
+#define mod 100000000
+#define M 0
+#define fastIO                        \
+    ios_base::sync_with_stdio(false); \
+    cin.tie(NULL);                    \
+    cout.tie(NULL)
+#define endl "\n"
+#define mp make_pair
+#define pb push_back
+#define pf push_front
+#define ub upper_bound
+#define lb lower_bound
+#define mod1 1000000009
+#define mem(a, val) memset(a, val, sizeof(a))
+#define vi vector<int>
+#define vvl vector<vector<long>>
+#define vl vector<ll>
+#define vpl vector<pair<ll, ll>>
+#define vpi vector<pair<int, int>>
+#define msi map<string, int>
+vi adj[100005];
+vi adjt[100005];
+int vis[100005];
+vi order; // for first dfs having increasing outtime order
+vi scc;
+void dfs(int v)
+{
+    vis[v] = 1;
+    for (auto x : adj[v])
+    {
+        if (!vis[x])
+        {
+            dfs(x);
+        }
+    }
+    order.pb(v);
+}
+void dfst(int v)
+{
+    vis[v] = 1;
+    for (auto x : adjt[v])
+    {
+        if (!vis[x])
+        {
+            dfst(x);
+        }
+    }
+    scc.pb(v);
+}
+
+int main()
+{
+    int t;
+    cin >> t;
+    while (t--)
+    {
+        int n, m, u, v;
+        cin >> n >> m;
+        for (int i = 1; i <= n; i++)
+        {
+            adj[i].clear(), adjt[i].clear(), vis[i] = 0;
+        }
+        order.clear();
+        for (int i = 1; i <= m; i++)
+        {
+            cin >> u >> v;
+            adj[u].pb(v);
+            adjt[v].pb(u);
+        }
+        for (int i = 1; i <= n; i++)
+        {
+            if (!vis[i])
+                dfs(i);
+        }
+        for (int i = 1; i <= n; i++)
+        {
+            vis[i] = 0;
+        }
+        for (int i = 1; i <= n; i++)
+        {
+            if (!vis[order[n - i]])
+            {
+                scc.clear();
+                dfst(order[n - i]);
+                cout << "dfst is called for" << order[n - i] << " " << endl;
+
+                for (int i : scc)
+                    cout << i << " ";
+                cout << endl;
+            }
+        }
+    }
+}

C++/Kruskal Algorithm.cpp

@@ -0,0 +1,76 @@
+//Name-Avnish Kumar
+//Github id-Avnish010
+#include <bits/stdc++.h>
+using namespace std;
+typedef long long int ll;
+#define mod 100000000
+#define M 0
+#define fastIO                        \
+    ios_base::sync_with_stdio(false); \
+    cin.tie(NULL);                    \
+    cout.tie(NULL)
+#define endl "\n"
+#define mp make_pair
+#define pb push_back
+#define pf push_front
+#define ub upper_bound
+#define lb lower_bound
+#define mod1 1000000009
+#define mem(a, val) memset(a, val, sizeof(a))
+#define vi vector<int>
+#define vvl vector<vector<long>>
+#define vl vector<ll>
+#define vpl vector<pair<ll, ll>>
+#define vpi vector<pair<int, int>>
+#define msi map<string, int>
+
+struct edge
+{
+    int u;
+    int v;
+    int w;
+};
+edge adj[100005];
+edge adj1[200005];
+int par[100005];
+bool comp(edge u, edge v)
+{
+    return u.w < v.w;
+}
+int find(int i)
+{
+    if (par[i] == -1)
+        return i;
+    return par[i] = find(par[i]);
+}
+void set_union(int a, int b)
+{
+    par[b] = a;
+}
+
+int main()
+{
+    int n, m, u, v, w;
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++)
+    {
+        par[i] = -1;
+    }
+    for (int i = 0; i < m; i++)
+    {
+        cin >> adj[i].u >> adj[i].v >> adj[i].w;
+    }
+    sort(adj, adj + m, comp);
+    ll ans = 0;
+    for (int i = 0; i < m; i++)
+    {
+        u = find(adj[i].u);
+        v = find(adj[i].v);
+        if (u != v)
+        {
+            ans += adj[i].w;
+            set_union(u, v);
+        }
+    }
+    cout << ans << endl;
+}

C++/Sparse Table.cpp

@@ -0,0 +1,83 @@
+//Name-Avnish Kumar
+//Github id-Avnish010
+#include <bits/stdc++.h>
+using namespace std;
+#define int long long int
+#define mod 1000000007
+
+#define fastIO                        \
+    ios_base::sync_with_stdio(false); \
+    cin.tie(NULL);                    \
+    cout.tie(NULL)
+#define endl "\n"
+#define mp make_pair
+#define pb push_back
+#define pf push_front
+#define lb lower_bound
+#define ub upper_bound
+#define vi vector<int>
+#define vpi vector<pair<int, int>>
+#define mi map<int>
+#define msi map<string, int>
+#define mii map<int, int>
+#define spi set<pair<int, int>>
+const int limit = 1e18;
+const int sz = 1000005;
+const int LOG = 17;
+int prelog[sz];
+int st[sz][LOG];
+int query(int l, int r) // O(1) tc
+{
+    int len = r - l + 1;
+    int k = prelog[len];
+    return min(st[l][k], st[r - (1 << k) + 1][k]);
+}
+
+void solve()
+{
+    int n;
+    cin >> n;
+    prelog[1] = 0;
+    for (int i = 2; i <= n; i++)
+    {
+        prelog[i] = prelog[i / 2] + 1;
+    }
+    int a[n];
+
+    for (int i = 0; i < n; i++)
+    {
+        cin >> a[i];
+    }
+    for (int i = 0; i < n; i++)
+    {
+        st[i][0] = a[i];
+    }
+    // preprocessing st[i][k]=startin at idx= i store min of(i,i+(1<<k))
+    // tc =nlog(n)
+    for (int k = 1; k < LOG; k++)
+    {
+        for (int i = 0; i + (1 << k) - 1 < n; i++)
+        {
+            st[i][k] = min(st[i][k - 1], st[i + (1 << (k - 1))][k - 1]);
+        }
+    }
+    int q;
+    cin >> q;
+    while (q--)
+    {
+        int l, r;
+        cin >> l >> r;
+        cout << query(l, r) << endl;
+    }
+}
+signed main()
+{
+    fastIO;
+
+    int t = 1;
+    cin >> t;
+    while (t--)
+    {
+        solve();
+    }
+}