| 71 | [Simplify Path](https://leetcode.com/problems/simplify-path) | [](src/SimplifyPath.java) | |

import java.util.LinkedList;

public class SimplifyPath {

private static final char SLASH = '/';

private static final String ROOT = "/";

private static final String GO_ONE_LEVEL_UP = "..";

private static final String STAY_WHERE_YOU_ARE = ".";

public String simplifyPath(String path) {

final LinkedList<StringBuilder> fragments = new LinkedList<>();

StringBuilder current = new StringBuilder();

for (int i = 0 ; i < path.length() ; i++) {

if (path.charAt(i) == SLASH) {

if (!isEmpty(current)) {

addToFragments(current, fragments);

current = new StringBuilder();

}

} else current.append(path.charAt(i));

}

if (!isEmpty(current)) addToFragments(current, fragments);

return toPath(fragments);

}

private String toPath(LinkedList<StringBuilder> fragments) {

if (fragments.isEmpty()) return ROOT;

StringBuilder result = new StringBuilder();

for (StringBuilder fragment : fragments) {

result.append(SLASH).append(fragment);

}

return result.toString();

}

private void removeLast(LinkedList<StringBuilder> fragments) {

if (!fragments.isEmpty()) {

fragments.removeLast();

}

}

private void addToFragments(StringBuilder current, LinkedList<StringBuilder> fragments) {

String currentString = current.toString();

if (GO_ONE_LEVEL_UP.equals(currentString)) {

removeLast(fragments);

} else if (!STAY_WHERE_YOU_ARE.equals(currentString)) {

fragments.add(current);

}

}

private boolean isEmpty(StringBuilder stringBuilder) {

return stringBuilder.length() == 0;

}

}