2024-07-13 15:19:22 -07:00
|
|
|
|
T Element((Int weight, [(Char, String)] symbols))
|
2023-07-01 11:58:00 -04:00
|
|
|
|
F <(other)
|
|
|
|
|
|
R (.weight, .symbols) < (other.weight, other.symbols)
|
|
|
|
|
|
|
|
|
|
|
|
F encode(symb2freq)
|
|
|
|
|
|
V heap = symb2freq.map((sym, wt) -> Element(wt, [(sym, ‘’)]))
|
|
|
|
|
|
minheap:heapify(&heap)
|
|
|
|
|
|
|
|
|
|
|
|
L heap.len > 1
|
|
|
|
|
|
V lo = minheap:pop(&heap)
|
|
|
|
|
|
V hi = minheap:pop(&heap)
|
|
|
|
|
|
|
|
|
|
|
|
L(&sym) lo.symbols
|
|
|
|
|
|
sym[1] = ‘0’sym[1]
|
|
|
|
|
|
|
|
|
|
|
|
L(&sym) hi.symbols
|
|
|
|
|
|
sym[1] = ‘1’sym[1]
|
|
|
|
|
|
|
|
|
|
|
|
minheap:push(&heap, Element(lo.weight + hi.weight, lo.symbols [+] hi.symbols))
|
|
|
|
|
|
|
|
|
|
|
|
R sorted(minheap:pop(&heap).symbols, key' p -> (p[1].len, p))
|
|
|
|
|
|
|
|
|
|
|
|
V txt = ‘this is an example for huffman encoding’
|
|
|
|
|
|
V symb2freq = DefaultDict[Char, Int]()
|
|
|
|
|
|
L(ch) txt
|
|
|
|
|
|
symb2freq[ch]++
|
|
|
|
|
|
|
|
|
|
|
|
V huff = encode(symb2freq)
|
|
|
|
|
|
print("Symbol\tWeight\tHuffman Code")
|
|
|
|
|
|
L(p) huff
|
|
|
|
|
|
print("#.\t#.\t#.".format(p[0], symb2freq[p[0]], p[1]))
|
