题解 | 括号配对问题

s=input()
stack=[]
for c in s:
    if c=='(' or c=='[' or c=='{':
        stack.append(c)
    elif c==')':
        if len(stack)>0 and stack[-1]=='(':
            stack.pop()
        else:
            print("false")
            exit()
    elif c==']':
        if len(stack)>0 and stack[-1]=='[':
            stack.pop()
        else:
            print("false")
            exit()
    elif c=='}':
        if len(stack)>0 and stack[-1]=='{':
            stack.pop()
        else:
            print("false")
            exit()
if len(stack) == 0:
    print("true")
else:
    print("false")