题解 | #字符流中第一个不重复的字符#

//Init module if you need
// 初始化
const map = new Map();
let s = '';
function Init() {
}
//Insert one char from stringstream
function Insert(ch) {
    s += ch;
    if(!map.has(ch)){
        map.set(ch, 1);
    }
    else{
        map.set(ch, map.get(ch) + 1);
    }
}
//return the first appearence once char in current stringstream
function FirstAppearingOnce() {
    for(let char of s){
        if(map.get(char) === 1) return char;
    }
    return '#';
}

module.exports = {
    Init: Init,
    Insert: Insert,
    FirstAppearingOnce: FirstAppearingOnce,
};