Given a string containing just the characters
'('
,
')'
,
'{'
,
'}'
,
'['
and
']'
, determine if the input string is valid.
The brackets must close in the correct order,
"()"
and
"()[]{}"
are all valid but
"(]"
and
"([)]"
are not.
验证一个字符串里的括号是否正确闭合 比较简单 代码如下
public boolean isValid(String s) {
Stack<Character> stack = new Stack<Character>();
for(char c : s.toCharArray()){
switch (c){
case '(':
case '{':
case '[':
stack.push(c);
break;
case ')':
if(stack.isEmpty() || stack.pop() != '(') return false;
break;
case '}':
if(stack.isEmpty() || stack.pop() != '{') return false;
break;
case ']':
if(stack.isEmpty() || stack.pop() != '[') return false;
break;
}
}
return stack.isEmpty();
}
代码已经很简洁了 但是没想到还有更骚的
public boolean isValid(String s) {
Stack<Character> stack = new Stack<Character>();
for (char c : s.toCharArray()) {
if (c == '(')
stack.push(')');
else if (c == '{')
stack.push('}');
else if (c == '[')
stack.push(']');
else if (stack.isEmpty() || stack.pop() != c)
return false;
}
return stack.isEmpty();
}每次遇到左括号就向stack中放入右括号 遇到右括号直接和栈顶比较是否相等
