71. 简化路径（算法200题-28）

/**
 * @param {string} path
 * @return {string}
 */
var simplifyPath = function(path) {
  const stack = []
           paths = path.split('/')
    for(let i = 0; i < paths.length; i++) {
      if(paths[i] === '..') {
        stack.pop()
      } else if(paths[i] && paths[i] !== '.') {
        stack.push(paths[i])
      }
    }
    return '/' + stack.join('/')
};