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SimplifyPath71.java
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SimplifyPath71.java
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package Leetcode;
import java.util.Stack;
public class SimplifyPath71 {
/**Method: Stack; Time: O(N); Space: O(N) **/
/**
1.定义一个辅助栈;
2.先把字符串以"/"为分隔符分割成数组,此时数组有"路径"、""、"."、".."这四种情况;
3.遍历数组,当s[i].equals("..")并且栈不空时pop,当!s[i].equals("") && !s[i].equals(".") && !s[i].equals(".."),即s[i]是路径入栈;
4.栈空,返回"/",栈非空,StringBuilder返回;
**/
public String simplifyPath(String path) {
String[] s = path.split("/");
Stack<String> stack = new Stack<>();
for (int i = 0; i < s.length; i++) {
if (!stack.isEmpty() && s[i].equals(".."))
stack.pop();
else if (!s[i].equals("") && !s[i].equals(".") && !s[i].equals(".."))
stack.push(s[i]);
}
if (stack.isEmpty())
return "/";
StringBuffer res = new StringBuffer();
for (int i = 0; i < stack.size(); i++) {
res.append("/" + stack.get(i));
}
return res.toString();
}
}