1、打开JUPYTER NOTEBOOK，新建一个空白的PY文档。
2、s = "()"if ("(" and ")" in s) or ("[" and "]" in s) or ("{" and "}" in s): print(True)else: print(False)很多同学会有多个IF来不断判断。
3、s = "(]"if ("(" and ")" in s) or ("[" and "]" in s) or ("{" and "}" in s): print(True)else: print(False)但是这样容易出错也很麻烦。
4、s = "(]"d = {"(": ")", "[": "]", "{": "}"}dd = {}for i in range(len(s)): dd[s[i]] = s[i+1]print(d)print(dd)于是开始有了字典储存符号的方法了。
5、s = "(]"d = {"(": ")", "[": "]", "{": "}"}if (len(s) % 2 != 0) or (len(s) == 0): print(False)else: for i in range(len(s)): if d[s[i]] != s[i+1]: print(False) break else: print(True)我们首先要解决超出范围的问题。
6、s = "()"d = {"(": ")", "[": "]", "{": "}"}if (len(s) % 2 != 0) or (len(s) == 0): print(False)else: for i in range(len(s)): if d[s[i]] != s[i+1]: print(False) break else: print(True) break
7、s = "({[]})"#it should be True.d = {"(": ")", "[": "]", "{": "}"}if (len(s) % 2 != 0) or (len(s) == 0): print(False)else: for i in range(len(s)): if d[s[i]] != s[i+1]: print(False) break else: print(True) break但是我们会发现这里就出错了。
8、s = "({[]})"#it should be True.d = {'(': ')', '[': ']', '{': '}'}if (len(s) % 2 != 0) or (len(s) == 0): print(False)else: for i in range(len(s)): for j in range(1, len(s)): if s[i] == d[s[j]]: print(True) break else: print(False) break有些同学会用两个循环来解决。
9、s = "()"d = {')': '(', '}': '{', ']': '['}temp = []for i in s: if i in d and d[i] == temp[len(temp)-1]: temp.pop() else: temp.append(i)if len(temp) == 0: print(True)else: print(False)但实际上简单的方法是要把字典的储存先更正过来。
10、s = ")"d = {')': '(', '}': '{', ']': '['}temp = []for i in s: if i in d and d[i] == temp[len(temp)-1]: temp.pop() else: temp.append(i)if len(temp) == 0: print(True)else: print(False)s = ")"d = {')': '(', '}': '{', ']': '['}temp = [None]for i in s: if i in d and d[i] == temp[len(temp)-1]: temp.pop() else: temp.append(i)if len(temp) == 0: print(True)else: print(False)为了不超出范围，我们一定要设置NONE。
11、s = "()"d = {')': '(', '}': '{', ']': '['}temp = [None]for i in s: if i in d and d[i] == temp[len(temp)-1]: temp.pop() else: temp.append(i)if len(temp) == 1: print(True)else: print(False)最后要设置长度的判断，才可以。
