/** * Given a binary Tree * 1 * / \ * 2 3 * / \ / \ * 4 5 6 7 * * Find vertical sums of the tree. * Align the nodes in vertical line. * Here * The tree has 5 vertical lines * * Vertical-Line-1 has only one node 4 => vertical sum is 4 * Vertical-Line-2: has only one node 2=> vertical sum is 2 * Vertical-Line-3: has three nodes: 1,5,6 => vertical sum is 1+5+6 = 12 * Vertical-Line-4: has only one node 3 => vertical sum is 3 * Vertical-Line-5: has only one node 7 => vertical sum is 7 * * So expected output is 4, 2, 12, 3 and 7 * */ #include <iostream> #include <unordered_map> #include <vector> #include <algorithm> #include <map> struct Node { int data; Node * left; Node * right; Node ( int d ) : data{ d }, left{ nullptr }, right{ nullptr } { } }; void vertical_sum_util( Node * root, int dist, std::unordered_map<int,int> & vmap) { if ( root == nullptr ) { return ; } if ( vmap.find(dist) != vmap.end() ) { vmap[dist] += root->data; } else { vmap[dist] = root->data; } vertical_sum_util( root->left, dist-1, vmap); vertical_sum_util( root->right, dist+1, vmap); } void vertical_sum( Node * root ) { if ( root == nullptr ) { return; } std::unordered_map<int, int> vmap; vertical_sum_util( root, 0, vmap ); std::map<int, int> ordered( vmap.begin(), vmap.end()); std::cout << "Printing vertical sum values, first column represent the position of vertical column with respect to root(0)\n" << "and second column represent vertical sum for that column\n"; for ( auto it = ordered.begin(); it != ordered.end(); ++it ) { std::cout << it->first << " " << it->second << std::endl; } } int main() { Node * root = new Node(1); root->left = new Node(2); root->right = new Node(3); root->left->left = new Node(4); root->left->right = new Node(5); root->right->left = new Node(6); root->right->right = new Node(7); vertical_sum(root); return 0; }