Add disjoint_set.cpp

Author: precisecharmer

disjoint set - Copy/code.cpp

@@ -0,0 +1,102 @@
+// This section is for Disjoint set data structure
+// when we find parent of any number in worst case we go O(n) so if for all the numbers on the path we directly make their parent as root
+// so when we make M number of operations and take thier average complexity that is alpha(n) which <= 4 for even biggest values
+// their is no difference in code except the part where we find parent there we add one more line for changing parent of every node on
+// the path
+
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+const int inf = 1e9 + 7;
+
+int find(vector<int> &parent, int x)
+{
+    if (parent[x] == x)
+    {
+        return x;
+    }
+    parent[x] = find(parent, parent[x]);
+    return parent[x];
+}
+
+void union_num(vector<int> &parent, vector<int> &rank, int num1, int num2)
+{
+    int fparent = find(parent, num1);
+    int sparent = find(parent, num2);
+    if (fparent == sparent)
+    {
+        return;
+    }
+    if (rank[fparent] < rank[sparent])
+    {
+        parent[fparent] = sparent;
+    }
+    else if (rank[fparent] > rank[sparent])
+    {
+        parent[sparent] = fparent;
+    }
+    else
+    {
+        parent[fparent] = sparent;
+        rank[sparent]++;
+    }
+}
+
+void solve()
+{
+    int n = 8; // 0 - 7
+    vector<int> parent(n), rank(n, 0);
+    for (int i = 0; i < n; i++)
+    {
+        parent[i] = i;
+    }
+    int total;
+    cin >> total;
+    while (total--)
+    {
+        int choice;
+        cin >> choice;
+        if (choice == 1)
+        {
+            // union
+            int num1, num2;
+            cin >> num1 >> num2;
+            union_num(parent, rank, num1, num2);
+        }
+        else
+        {
+            // find
+            int num1, num2;
+            cin >> num1 >> num2;
+            int fparent = find(parent, num1), sparent = find(parent, num2);
+
+            if (fparent == sparent)
+            {
+                cout << "They are in same group!!" << endl;
+            }
+            else
+            {
+                cout << "They are not in same group!!" << endl;
+            }
+        }
+
+        cout << "Check parent array: " << endl;
+        for (int i = 0; i < parent.size(); i++)
+        {
+            cout << parent[i] << " ";
+        }
+        cout << endl;
+        cout << "Check Rank array: " << endl;
+        for (int i = 0; i < rank.size(); i++)
+        {
+            cout << rank[i] << " ";
+        }
+        cout << endl;
+    }
+}
+
+int main()
+{
+    solve();
+    return 0;
+}

disjoint set - Copy/readme.txt

@@ -0,0 +1,8 @@
+This section is for Disjoint set data structure
+
+
+First one is basic one which adds first over second whithout any optimisation
+
+second one sees height of tree and add according to that
+
+Third one makes average time complexity <= 4 because it makes parent of every node as root during any normal find function