Finding the most black nodes in a binary tree

Problem:given a tree, color nodes black as many as possible without coloring, adjacent nodes

Idea: If the root node R is marked black, its immediate child node cannot be marked black, and if R is not marked, its child nodes can be marked black, resulting in a state transition equation:

Find (r) = Max (Black (R), White (R))

Black (R) is the number of nodes in the tree with the r root node that can be marked as dark when node R is marked as Black

White (R) is the number of nodes in the tree with r root that can be marked as black when node R is not marked as black

The

White (R) = Find (R.left) + Find (r.right)

When r is not marked as black, the left and right child nodes continue to look for

Black (r) = 1 + whilte (r.left) + White (r.right)

When R is marked black, it contributes 1 to the total number of black nodes, and then its left and right child nodes must be non-black nodes.

1  Packagecom.self;2 3  Public classDp_03_tree {4 5      Public Static voidMain (string[] args) {6         7Node node4 =NewNode (4);8Node Node3 =NewNode (3);9Node NODE5 =NewNode (5);TenNode Node2 =NewNode (2); OneNode Node1 =NewNode (1); A          -Node4.left =Node3; -Node4.right =Node5; theNode3.left =Node2; -Node3.right =Node1; -          -Dp_03_tree app =NewDp_03_tree (); +         intMaxblack =App.find (NODE4); - System.out.println (maxblack); +     } A      at     intFind (Node node) { -         if(NULL= = node)return0; -         if(NULL= = Node.left &&NULL= = Node.right)return1; -         returnMath.max (Findfromwhite (node), Findfromblack (node)); -     } -      in     //Current node was white -     intFindfromwhite (node node) { to         if(NULL= = node)return0; +         returnFind (Node.left) +find (node.right); -     } the      *     //Current node is black $     intFindfromblack (node node) {Panax Notoginseng         if(NULL= = node)return0; -         //Current node was black, then its children does not count, but itself counts the         return1 + findfromwhite (node.left) +Findfromwhite (node.right); +     } A } the  + classnode{ -     intv; $ Node left; $ Node right; -Node (intv) { -          This. v =v; the     } -}

Finding the most black nodes in a binary tree