给定一个只包括 '(',')','{','}','[',']' 的字符串 s ,判断字符串是否有效。
有效字符串需要满足:
左括号必须用相同类型的右括号闭合。例如:"[]","()","{}"
左括号必须以正确的顺序闭合。例如:"[()]"
每个右括号都有一个对应的相同类型的左括号。例如:"[()]{}"
package learnProject.csdn;/*** * @author Roc-xb**/
public class ValidParentheses {public static boolean isValid(String s) {if (s == null || s.length() == 0)return false;char[] stack = new char[s.length()];int head = 0;for (char c : s.toCharArray()) {switch (c) {case '{':case '[':case '(':stack[head++] = c;break;case '}':if (head == 0 || stack[--head] != '{') {return false;}break;case ')':if (head == 0 || stack[--head] != '(') {return false;}break;case ']':if (head == 0 || stack[--head] != '[') {return false;}break;}}return head == 0;}public static void main(String[] args) {System.out.println(isValid(null));}
}