You are asked to design a file system that allows you to create new paths and associate them with different values.
The format of a path is one or more concatenated strings of the form: /
followed by one or more lowercase English letters. For example, "/leetcode"
and "/leetcode/problems"
are valid paths while an empty string ""
and "/"
are not.
Implement the FileSystem
class:
bool createPath(string path, int value)
Creates a new path
and associates a value
to it if possible and returns true
. Returns false
if the path already exists or its parent path doesn't exist.int get(string path)
Returns the value associated with path
or returns -1
if the path doesn't exist.
Example 1:
Input: ["FileSystem","createPath","get"] [[],["/a",1],["/a"]] Output: [null,true,1] Explanation: FileSystem fileSystem = new FileSystem(); fileSystem.createPath("/a", 1); // return true fileSystem.get("/a"); // return 1
Example 2:
Input: ["FileSystem","createPath","createPath","get","createPath","get"] [[],["/leet",1],["/leet/code",2],["/leet/code"],["/c/d",1],["/c"]] Output: [null,true,true,2,false,-1] Explanation: FileSystem fileSystem = new FileSystem(); fileSystem.createPath("/leet", 1); // return true fileSystem.createPath("/leet/code", 2); // return true fileSystem.get("/leet/code"); // return 2 fileSystem.createPath("/c/d", 1); // return false because the parent path "/c" doesn't exist. fileSystem.get("/c"); // return -1 because this path doesn't exist.
Constraints:
104
in total.2 <= path.length <= 100
1 <= value <= 109
use std::collections::HashMap;
#[derive(Default)]
struct FileSystem {
paths: HashMap<String, i32>,
}
impl FileSystem {
fn new() -> Self {
FileSystem {
paths: HashMap::new(),
}
}
fn create_path(&mut self, path: String, value: i32) -> bool {
let index = path.rfind('/').unwrap();
let parent = &path[0..index];
if !self.paths.contains_key(&path) && (parent.is_empty() || self.paths.contains_key(parent))
{
self.paths.insert(path, value);
true
} else {
false
}
}
fn get(&self, path: String) -> i32 {
*self.paths.get(&path).unwrap_or(&-1)
}
}
#[test]
fn test() {
let mut fs = FileSystem::new();
assert_eq!(fs.create_path("/leet".to_string(), 1), true);
assert_eq!(fs.create_path("/leet/code".to_string(), 2), true);
assert_eq!(fs.get("/leet/code".to_string()), 2);
assert_eq!(fs.create_path("/c/d".to_string(), 2), false);
assert_eq!(fs.get("/c".to_string()), -1);
}