How to take the inputs?

#1

how i can build the tree using bfs level by level

#2 
node *buildtree()
{
    int a;
    cin>>a;
    node *root = new node(a);
    queue<node*> q;
    q.push(root);

    while(!q.empty())
    {
        cin>>a;
        if(a!=-1)
        {
            node *temp = new node(a);
            if(q.front()->left==NULL)
            q.front()->left = temp;
            else
            {
                q.front()->right = temp;
                q.pop();
            }
            q.push(temp);
        }
        else
        {
            if(q.front()->left==NULL)
            {
                cin>>a;
                if(a==-1)
                    q.pop();
                else
                {
                    node *temp1=new node(a);
                    q.front()->right = temp1;
                    q.pop();
                    q.push(temp1);
                }
            }
            else
                q.pop();
        }
    }
    return root;
}

int main()
{
    int h;
    cin>>h;
    node *root = buildtree();
}

This piece of code should help.

#3

node * levelOrderInput() {

// Create Queue to store the left and the right childrens 
int data; cin >> data; 

queue<node *> q; 
node *root = new node(data); 
q.push(root); 

while(!q.empty()) {

    node *f = q.front(); 
    q.pop(); 

    int c1, c2; cin >> c1 >> c2; 
    
    if(c1 != -1) {
        f->left = new node(c1);
        q.push(f->left);
    }

    if(c2 != -1) {
        f->right = new node(c2);
        q.push(f->right); 
    }
}
return root;

}

this one is correct??

#4

And one for question :
for(auto p : m) {
for (int x : p.second) {
cout << x << " ";
}
cout << endl;
}

if i used this notations p->second instead of p.second it showing me error

#5

You can try and check for different inputs. You have both the codes now so you can do it by yourself.

#6

p.second is used for pairs and p->second is used for map iterators.

#7

@S19APP-PP0108 okay got it …

#8

helperVerticalOrder(root, 0, m);
vector<vector> v;
// Print the value of the hashmaps
for(auto p : m) {
vector temp;
for(int x : p.second) {
temp.push_back(x);
}
v.push_back(temp);
}

for(auto it = v.begin(); it != v.end(); it++) {
    // 
}

how i can insert the value in the 2 d vectors i am little confused how to iterate in vectors of vectors

#9

Declare a 2D vector with size only like - vector<vector > v(n,vector(m));
Then you can use it like a 2D array only.

for(int i=0; i<n; i++)
     for(int j=0; j<m; j++)
        cin>>v[i][j]
#10

okay got it @S19APP-PP0108

#11

Cool. Please mark your doubt as resolved now.

#12

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