字符串解压缩问题——贪心算法

 

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69

import sys     def load_data():     return sys.stdin.read()     def get_position_map(s):     result = {}     stack = []     for i,c in enumerate(s):         if c == "[":             result[i] = -1             stack.append(i)         elif c == "]":             if stack:                 pos = stack.pop()                 result[pos] = i     return result     def decode_str(s, start, end, pos_map):     def in_range(i, start, end):         return start<=i<end       def is_str(c):         return ord('a')<=ord(c)<=ord('z') or ord('A')<=ord(c)<=ord('Z')       def is_num(c):         return ord('0') <= ord(c) <= ord('9')       result = ""     i = start     while in_range(i, start, end):         string = ""         while in_range(i, start, end) and is_str(s[i]):             string += s[i]             i += 1           if not in_range(i, start, end):             return string           digit = ""         while in_range(i, start, end) and is_num(s[i]):             digit += s[i]             i += 1           if not in_range(i, start, end):             return string           if pos_map[i] == -1:             return string           d_str = decode_str(s, i+1, pos_map[i], pos_map)         result += string + d_str*int(digit)           i = pos_map[i]+1     return result     def main():     encoded_str = load_data() # "abc3[xyz4[mn]" # "abc3[xyz"  # "abc2[xyz3[mn]]" #"aaabcbc" #"3[a]2[bc]"     pos_map = get_position_map(encoded_str)     decoded_str = decode_str(encoded_str, 0, len(encoded_str), pos_map)     print(decoded_str)     if __name__ == "__main__":     main()