leetcode 100: Simplify Path

Simplify PathApr 4 '12

Given an absolute path for a file (Unix-style), simplify it.

For example,
path = "/home/", => "/home"
path = "/a/./b/../../c/", => "/c"

Corner Cases:

• Did you consider the case where path = "/../"?
  In this case, you should return "/".
• Another corner case is the path might contain multiple slashes '/' together, such as "/home//foo/".
  In this case, you should ignore redundant slashes and return "/home/foo".

HAPPY 100. my goal 300~  

 

 

public class Solution {
    public String simplifyPath(String path) {
        // Start typing your Java solution below
        // DO NOT write main() function
        //path = "/a/./b/../../c/", => "/c"
        
        if(path==null) return null;
        
        String[] strs = path.split("/");
        Stack<String> stack = new Stack<String>();
        
        for( int i=0; i<strs.length; i++) {
            String s = strs[i];
            if( s.equals(".") || s.length()==0) {//!alert: s.length==0 or u will have many ////.
                 continue;
            } else if(s.equals("..") ) {
                if(!stack.isEmpty()){
                    stack.pop();
                }
            } else {
                stack.push(s);
            } 
        }
        
        StringBuilder sb = new StringBuilder();
        
        while(!stack.isEmpty()) {
            sb.insert(0, stack.pop() );
            sb.insert(0, "/");
        }
        
        if(sb.length()==0) sb.insert(0, "/");
        return sb.toString();
    }
}