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| from random import randint | |
| def find_components(raw_array, value): | |
| """ | |
| ~O(n) find first combination in `new_array` which sum equal `value`. | |
| """ | |
| # remove from array all values grand then needed value | |
| array = list(filter(lambda x: x <= value, raw_array)) | |
| # keep only unique values | |
| array = list(set(array)) | |
| # sort big to small | |
| array = sorted(array, reverse=True) | |
| for number in array: | |
| if number == value: | |
| return [number] | |
| # remove number from array, because if does not exists combinations | |
| # with him, then we don't need recombinate it in other cycle | |
| array.remove(number) | |
| # get remainder value | |
| diff = value - number | |
| # copy remainder array | |
| _copy = list(array) | |
| # find in remainder array other summ components for that number | |
| sub_components = find_components(_copy, diff) | |
| if sub_components: | |
| return [number] + sub_components | |
| return [] | |
| arr = map(lambda x: randint(1, 10000), range(0, 1000)) | |
| need = randint(1, 20000) | |
| need_combinations = find_components(list(arr), need) | |
| if need_combinations: | |
| msg = "for number {} founded combination {} with summ {}" | |
| print(msg.format(need, need_combinations, sum(need_combinations))) | |
| else: | |
| print("does not have combinations") |
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