71. Simplify Path

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

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

click to show corner cases.

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stack

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public class Solution {
    public String simplifyPath(String path) {
        if (path == null || path.length() == 0) return "/";
    
        Stack<String> stack = new Stack<String>();
        String[] splits = path.trim().split("/");
        for (String s : splits) {
            if (s == null || s.length() == 0 || s.equals(".")) {
                // Do nothing;
            } else if (s.equals("..")) {
                // Pop if stack is not empty;
                if (stack.size() > 0) stack.pop();
            } else {
                // Push all others to stack.
                stack.push(s);
            }
        }
    
        // Remember, stack can be empty.
        if (stack.isEmpty()) return "/";
    
        StringBuffer buf = new StringBuffer();
        while (!stack.isEmpty()) {
            buf.insert(0, stack.pop());
            buf.insert(0, "/");
        }
    
        return buf.toString();
    }
}