去除字符

[TieMuZhen]

对输入的字符串，去除其中的字符'b'以及连续出现的'a'和'c'
例如：
'aacbd' -> 'ad'
'aabcd' -> 'ad'
'aaabbccc' -> ''

function _firter(s) {
    let stack = [];
    for (let i = 0; i < s.length; i ++) {
        if(s[i] === 'b') continue;
        if (stack.length) {
            if (s[i] === 'c' && stack[stack.length - 1] === 'a') {
                stack.pop();
                continue;
            }
        }
        stack.push(s[i]);
    }
    return stack.join('');
}
 
let a = 'aaabbccc';
let r = _firter(a);
console.log(r);