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79. Calculate Distance Between Nodes in a Binary Tree
Objective: - Given two nodes in a binary tree, find the distance between them.
Example :
Approach:
- Distance(X, Y) = Distance(root, X) +Distance(root, Y) - 2*(Distance(root to LCA(X,Y)
- where LCA(X,Y) = Lowest Common Ancestor of X,Y
- In the above example if Distance(20,45) = 3
- Distance(root, 20) = 2
- Distance(root, 45) = 3
- LCA(20, 45) = 10
- Distance(root, 10) = 1
- Distance(20,45) = 2+3 - 2*1 = 3
Now the problem is reduced to How to find the distance from the root to any given node and How to find Lowest Common Ancestor of two given nodes.
Output:
Distance between 45 and 20 is : 3