Merge pull request wangzheng0822#383 from caitlingao/feat-rust-35-trie

feat(geektime_algo): add 35 trie

Author: wangzheng0822

rust/35_trie/trie.rs

@@ -0,0 +1,41 @@
+// [leetcode 208](https://leetcode.com/problems/implement-trie-prefix-tree/)
+
+#[derive(Default, Debug)]
+struct Trie {
+    is_ending: bool,
+    nodes:     [Option<Box<Trie>>; 26],
+}
+
+impl Trie {
+    fn new() -> Self {
+        Default::default()
+    }
+
+    fn insert(&mut self, word: &str) {
+        let mut curr = self;
+        for i in word.chars().map(|c| (c as usize - 'a' as usize) as usize) {
+            curr = curr.nodes[i].get_or_insert_with(|| Box::new(Trie::new()));
+        }
+        curr.is_ending = true;
+    }
+
+    fn find(&self, word: &str) -> bool {
+        let mut curr = self;
+        for i in word.chars().map(|c| (c as usize - 'a' as usize) as usize) {
+            match curr.nodes[i].as_ref() {
+                Some(node) => { curr = node; },
+                None => { return false; },
+            }
+        }
+        curr.is_ending
+    }
+}
+
+fn main() {
+    let mut m = Trie::new();
+    m.insert("hello");
+    m.insert("she");
+    println!("{:?}", m);
+    let r = m.search("hello");
+    println!("{}", r); // true
+}