Merge pull request keshavsingh4522#683 from HarshitGupta150/master

Create diameter-of-generic-tree CPP Code

CPP/Data Structures/Trees/Generic Trees/diameter-of-generic-tree

@@ -0,0 +1,168 @@
+#include <bits/stdc++.h>
+#include <vector>
+#include <stack>
+
+using namespace std;
+
+struct Node
+{
+ int data;
+ vector<Node *> children;
+};
+
+Node *construct(int arr[], int n)
+{
+ Node *root = NULL;
+ stack<Node *> st;
+ for (int i = 0; i < n; i++)
+ {
+ if (arr[i] == -1)
+ {
+ if (st.size() != 0)
+ st.pop();
+ }
+ else
+ {
+ Node *t = new Node();
+ t->data = arr[i];
+
+ if (st.size() > 0)
+ {
+ Node *top = st.top();
+ top->children.push_back(t);
+ }
+
+ else
+ {
+ root = t;
+ }
+ st.push(t);
+ }
+ }
+ return root;
+};
+
+int size(Node *node)
+{
+ int s = 0;
+
+ for (int i = 0; i < node->children.size(); i++)
+ {
+ s += size(node->children[i]);
+ }
+ s += 1;
+
+ return s;
+}
+
+vector <int> galvin(Node *root, int b){
+ if(root->data == b){
+ vector <int> path;
+ path.push_back(root->data);
+ return path;
+ }
+
+ for(Node *child: root->children){
+ vector<int> ptc = galvin(child, b);
+ if(ptc.size() > 0){
+ ptc.push_back(root->data);
+ return ptc;
+ }
+ }
+ return vector<int>();
+
+
+ }
+
+ int distanceBetweenNodes(Node *root, int d1, int d2){
+ vector<int> p1=galvin(root, d1);
+ vector<int> p2=galvin(root, d2);
+
+ int i = p1.size() - 1;
+ int j = p2.size() - 1;
+
+ while(i >= 0 && j >= 0 && p1[i] == p2[j]){
+ i--;
+ j--;
+ }
+
+
+ return i+1 + j+1;
+ }
+
+
+ bool areSimilar(Node *root,Node *node)
+ {
+ if(root->children.size()!=node->children.size())
+ return false;
+
+ for (int i = 0; i < node->children.size() ; i++) {
+ Node *c1 = root->children[i];
+ Node *c2 = node->children[i];
+ if (areSimilar(c1, c2) == false) {
+ return false;
+ }
+ }
+
+ return true;
+ }
+
+
+void display(Node *root)
+{
+ if(root == NULL)return;
+ string str = to_string(root->data) + "->";
+ for (Node* child : root->children)
+ {
+ str +=to_string(child->data) + ",";
+ }
+ str += ".";
+ //cout << (str) << endl;
+
+ // for (Node * child : root->children)
+ // {
+ // display(child);
+ // }
+}
+
+
+static int dia=0;
+
+int diameter(Node *root)
+{
+ int ht=-1;
+ int sh=-1;
+
+ for (Node *child : root->children) {
+ int ch = diameter(child);
+ if (ch >= ht) {
+ sh = ht;
+ ht = ch;
+ } else if (ch >= sh) {
+ sh = ch;
+ }
+ }
+
+ if (sh + ht + 2 > dia) {
+ dia = sh + ht + 2;
+ }
+
+ ht += 1;
+ return ht;
+
+
+}
+
+
+int main()
+{
+ int n;
+ cin >> n;
+ int arr[n];
+ for (int i = 0; i < n; i++)
+ cin >> arr[i];
+ Node *root = construct(arr, n);
+ dia = 0;
+ diameter(root);
+ cout<<dia<<endl;
+ }