import java.util.Stack; public class Solution { public String simplifyPath(String path) { if(path==null||path.length()<=1) return path; Stack stack = new Stack(); for(int i = 0;i1&&stack.peek()!='/') stack.pop(); i++; }else if(i+2==path.length()&&path.substring(i, i+2).equals("..")){ //判断/.. 返回上一个目录 stack.pop();//弹出当前目录 while(stack.size()>1&&stack.peek()!='/') stack.pop(); i++; }else{ while(i!=path.length()&&path.charAt(i)!='/') stack.add(path.charAt(i++)); if(i!=path.length()) i--; } } else stack.add(path.charAt(i)); } if(stack.isEmpty()) stack.add('/'); else if(stack.peek()=='/'&&stack.size()!=1) stack.pop(); char[] result = new char[stack.size()]; for(int i = result.length-1;i>=0;i--){ result[i] = stack.pop(); } return new String(result); } }