스택 (Last In First Out)
function solution(s) {
let stack = [];
stack.push(s[0]);
for (let i=1; i<s.length; i++) {
if (stack[stack.length-1] === s[i]) {
stack.pop();
}
else {
stack.push(s[i]);
}
}
if (stack.length === 0) return 1;
else return 0;
}
console.log(solution("baabaa"));