Valid Parentheses

来源：互联网发布：linux安装spark 编辑：程序博客网时间：2024/06/16 14:40

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.

public class Solution {    public boolean isValid(String s) {    if(s==null){    return false;    }    Stack<Character> stack = new Stack<Character>();    for(int i = 0;i<s.length();i++){    if(s.charAt(i)=='('||s.charAt(i)=='{'||s.charAt(i)=='['){    stack.push(s.charAt(i));    continue;    }    switch(s.charAt(i)){    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;    }    }    if(stack.isEmpty()){    return true;    }else{    return false;    }    }}

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