20. 有效的括号

作者:Annan

更新于:几秒前

字数统计:102 字

阅读时长:1 分钟

阅读量:

思路：后进的右括号匹配到左括号，左括号就弹出，符合后进先出

var isValid = function (s) {
    if(s.length%2!==0) return false

    let stack = []
    for(let i = 0;i < s.length;i ++) {
        const curStr = s[i]
        const map = new Map([['[',']'],['{','}'],['(',')']])
        const isLeft = ['{','(','['].includes(curStr)
        if(isLeft) {
            stack.push(curStr)
        } else {
            if(stack.length === 0) return false
            const lastStr = stack[stack.length - 1]
            if(map.get(lastStr) === curStr) {
                stack.pop()
            } else {
                return false
            }
        }
    }
    return stack.length === 0
};

Contributors

Annan