Minimum Remove to Make Valid Parentheses
var minRemoveToMakeValid = function(str) { str = str.split(""); let stack = []; for(let i = 0; i<str.length; i++){ if(str[i]==="(") stack.push(i); else if(str[i]===")"){ if(stack.length) stack.pop(); else str[i]=""; } } for(let i of stack) str[i] = ""; return str.join(""); }