function solution(number, k) {
number=number.split('').map((n)=>Number(n));
let stack=[];
for(let i=0;i<number.length;i++){
while(stack.length>0&&stack[stack.length-1]<number[i]&&k>0){
stack.pop();
k--;
}
stack.push(number[i]);
}
stack.splice(stack.length-k,k); // number:543231 k:2 for 문 통과후 여전히 k>0
return stack.join('');
}