Draw an optimal binary tree with weights of 1, 2, 2, 3 and 4, and calculate their weights.

The problem of Huffman tree

1，2->3 2 3 3( 1,2) 4

2，3->5 3( 1,2) 4 5(2,3)

3，4->7 5(2,3) 7(4,3( 1,2))

5,7->12 ... done

Trees are difficult to draw. . . Look at the problem-solving process above and draw it.

Explain whether the following reasoning is correct.

Introduce (1) (arbitrary x)F(x)→G(x).

(2)F(y)→G(y) US( 1)。

I don't see any problem with this. . . I haven't studied for so long, I forgot. . .

Fill in the blanks:

(1) If a = {1, 2}, r = {

(1) reflexive closure ~ Because the relation matrix of R is empty, its reflexive closure should be a identity matrix.

The others are too long to type. Please contact me again. . .