finish trim a binary search tree

14-50/trim-a-binary-search-tree/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "trim-a-binary-search-tree"
+version = "0.1.0"
+authors = ["Checky Hu <[email protected]>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

14-50/trim-a-binary-search-tree/src/main.rs

@@ -0,0 +1,80 @@
+use std::cell::RefCell;
+use std::env;
+use std::rc::Rc;
+use std::str::FromStr;
+
+#[derive(Debug, PartialEq, Eq)]
+struct TreeNode {
+    val: i32,
+    left: Option<Rc<RefCell<TreeNode>>>,
+    right: Option<Rc<RefCell<TreeNode>>>,
+}
+
+impl TreeNode {
+    #[inline]
+    fn new(val: i32) -> Self {
+        TreeNode {
+            val,
+            left: None,
+            right: None,
+        }
+    }
+}
+
+struct Solution {}
+
+impl Solution {
+    fn trim_bst_loop(
+        node: Option<&Rc<RefCell<TreeNode>>>,
+        low: i32,
+        high: i32,
+    ) -> Option<Rc<RefCell<TreeNode>>> {
+        if let Some(x) = node {
+            let v = x.borrow();
+            if v.val < low {
+                Solution::trim_bst_loop(v.right.as_ref(), low, high)
+            } else if v.val <= high {
+                let mut node = TreeNode::new(v.val);
+                node.left = Solution::trim_bst_loop(v.left.as_ref(), low, high);
+                node.right = Solution::trim_bst_loop(v.right.as_ref(), low, high);
+                Some(Rc::new(RefCell::new(node)))
+            } else {
+                Solution::trim_bst_loop(v.left.as_ref(), low, high)
+            }
+        } else {
+            None
+        }
+    }
+
+    pub fn trim_bst(
+        root: Option<Rc<RefCell<TreeNode>>>,
+        low: i32,
+        high: i32,
+    ) -> Option<Rc<RefCell<TreeNode>>> {
+        Solution::trim_bst_loop(root.as_ref(), low, high)
+    }
+}
+
+fn main() {
+    let mut ret: usize = 0;
+    let mut low: i32 = 0;
+    for (index, arg) in env::args().enumerate() {
+        match index {
+            0 => (),
+            1 => low = i32::from_str(&arg).expect("Error parse."),
+            _ => {
+                ret += 1;
+                let high: i32 = i32::from_str(&arg).expect("Error parse.");
+                let mut node = TreeNode::new(2);
+                node.left = Some(Rc::new(RefCell::new(TreeNode::new(1))));
+                node.right = Some(Rc::new(RefCell::new(TreeNode::new(3))));
+                Solution::trim_bst(Some(Rc::new(RefCell::new(node))), low, high);
+                break;
+            }
+        }
+    }
+
+    if 0 == ret {
+        println!("Require at least 2 parameters.");
+    }
+}