1, sort the current series to reduce it;
2. Starting from S[2], count the following S[ 1] numbers-1 (using node degree);
3. Loop until the current sequence is negative (i.e. unpatterable), or exit when the current sequence is all 0 (paintable).
For example, the sequence S: 7, 7, 4, 3, 3, 2, 1 deletes the first item 7 of the sequence S, and subtracts 1 from the next seven items to get: 6, 3, 2, 2, 1, 0, and continues to delete the first items 6, 6 of the sequence.
Extended data:
This tree is n (n > 0) A finite set of nodes (in other words, a tree is composed of nodes). When n=0, it is called an empty tree.
In any non-empty tree:
(1) only one node is called the root of the tree;
(2) Other nodes except the root node can be divided into a finite number of unrelated sets, and each set itself is a tree, which is called the subtree of the root.
This is a recursive definition, that is, the tree is used in the definition of the tree. The definition of a tree shows the characteristics of a tree, that is, a tree consists of a root node and several subtrees, which can be composed of several smaller subtrees. Every node in the tree is the root node of a subtree in the tree.
Baidu encyclopedia-node degree
Baidu Encyclopedia -Havel_Hakimi Algorithm