import java.util.Stack;
/**
* 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".
*/
public class SimplifyUnixPath {
public static void main(String[] args) {
String s1 = "//../";
System.out.println(simplifyUnixPath(s1));
String s2 = "/a/./.b//../c/";
System.out.println(simplifyUnixPath(s2));
String s3 = "/home/of/foo/../../bar/../is/.//here/.";
System.out.println(simplifyUnixPath(s3));
String s4 = "/home/of/foo/../";
System.out.println(simplifyUnixPath(s4));
}
public static String simplifyUnixPath(String path) {
Stack pathStack = new Stack();
String dir = "";
for (int i = 0; i < path.length(); i++) {
char c = path.charAt(i);
if (c != '/') {
dir += c;
continue;
}
// only "/"
if (dir.length() == 0)
continue;
if (dir.charAt(0) == '.') {
if (dir.length() > 1) {
if (dir.charAt(1) == '.') {
// dir /..ab/
if (dir.length() > 2) {
pathStack.push(dir);
} else {
// dir /../
if (pathStack.size() > 0) {
pathStack.pop();
}
}
} else {
// dir /.ab/
pathStack.push(dir);
}
}
// current path, do nothing
} else { // one dir
pathStack.push(dir);
}
// clear dir for next one
dir = "";
}
String finalPath = "";
for (int i = 0; i < pathStack.size(); i++) {
finalPath += "/" + pathStack.get(i);
}
if (pathStack.size() == 0)
finalPath = "/";
return finalPath;
}
}