题解 | #点击消除#

let stack = [];
for (let i = 0; i < line.length; ) {
  if (line[i] === stack[stack.length - 1]) {
    stack.pop();
  } else {
    stack.push(line[i]);
  }
  i++;
}
if (stack.length == 0) {
  console.log("0");
} else {
  console.log(stack.join(""));
}