python实现括号匹配的思路详解

# -*- coding: utf8 -*-
# 符号表
SYMBOLS = {'}': '{', ']': '[', ')': '(', '>': '<'}
SYMBOLS_L, SYMBOLS_R = SYMBOLS.values(), SYMBOLS.keys()
def check(s):
  arr = []
  for c in s:
    if c in SYMBOLS_L:
      # 左符号入栈
      arr.append(c)
    elif c in SYMBOLS_R:
      # 右符号要么出栈，要么匹配失败
      if arr and arr[-1] == SYMBOLS[c]:
        arr.pop()
      else:
        return False
  return True
print(check("3 * {3 +[(2 -3) * (4+5)]}"))
print(check("3 * {3+ [4 - 6}]"))

# 存储左括号和右括号
open_brackets = '([{<'
close_brackets = ')]}>'
# 映射左右括号便于出栈判断
brackets_map = {')': '(', ']': '[', '}': '{', '>': '<'}
# 对于每一行数据，进行如下判定若括号为左括号，加入栈，若括号为右括号，判断是否跟栈尾括号对应，
 若对应，弹出栈尾元素，若所有括号均正确闭合，则最后栈为空。
for row in rows:
  stack = []
  label = True
  for char in row:
    if char in open_brackets:
      stack.append(char)
    elif char in close_brackets:
      if len(stack) < 1:
        label = False
        break
      elif brackets_map[char] == stack[-1]:
        stack.pop()
      else:
        label = False
        break
    else:
      continue
  if stack != []:
    label = False
  print(label)
rows = [
'([<^>x[ ]{a}]{/}{t}g<^>)<{x}b>{x}<z({%}w >[b][c[c]]{<h>{h}}',
 '[/]{((x)({{*}*}w)w){f}{v}[%(^[z]{u}{ })([[ ]-]h)]{c}(*)[y]}',
 '<<(^)z>>[b]< >[[(c)u[v]{z<b< >><b>}]g][/b[(])v(v)(+)](v)',
 '[[b]][(v)g]<z>([{{<->+}e}[*]d<+>]g[[a] <+>(v){b}<e>]){a}[u]']

#!usr/bin/env python
# encoding:utf-8
def bracket_mathch(one_str):
  '''''
  括号匹配
  '''
  tmp_list = []
  open_bracket_list = ['(', '[', '{', '<', '《']
  close_bracket_list = [')', ']', '}', '>', '》']
  one_str_list = list(one_str)
  length = len(one_str_list)
  set_list = list(set(one_str_list))
  num_list = [one_str_list.count(one) for one in set_list]
  if one_str[0] in close_bracket_list:
    return False
  elif length % 2 != 0:
    return False
  elif len(set_list) % 2 != 0:
    return False
  else:
    for i in range(length):
      if one_str[i] in open_bracket_list:
        tmp_list.append(one_str[i])
      elif one_str[i] in close_bracket_list:
        if close_bracket_list.index(one_str[i]) == open_bracket_list.index(tmp_list[-1]):
          tmp_list.pop()
        else:
          return False
          break
  return True
if __name__ == '__main__':
  one_str_list = ['({})', '({[<《》>]})', '[(]){}', '{{{{{{', '([{}])', '}{[()]']
  for one_str in one_str_list:
    if bracket_mathch(one_str):
      print(one_str, '正确')
    else:
      print(one_str, '错误')
  tmp = '{}[{()()[]<{{[[[[(())()()(){}[]{}[]()<>]]]]}}>}]'
  print(bracket_mathch(tmp))