finish maximum binary tree

14-50/maximum-binary-tree/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "maximum-binary-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/maximum-binary-tree/src/main.rs

@@ -0,0 +1,74 @@
+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 construct_maximum_binary_tree_loop(
+        nums: &[i32],
+        left: usize,
+        right: usize,
+    ) -> Option<Rc<RefCell<TreeNode>>> {
+        if left >= right {
+            None
+        } else {
+            let mut max: (usize, i32) = (left, nums[left]);
+            for (i, v) in nums.iter().enumerate().take(right).skip(left + 1) {
+                if *v > max.1 {
+                    max.0 = i;
+                    max.1 = *v;
+                }
+            }
+            let mut node = TreeNode::new(max.1);
+            node.left = Solution::construct_maximum_binary_tree_loop(nums, left, max.0);
+            node.right = Solution::construct_maximum_binary_tree_loop(nums, max.0 + 1, right);
+            Some(Rc::new(RefCell::new(node)))
+        }
+    }
+
+    pub fn construct_maximum_binary_tree(nums: Vec<i32>) -> Option<Rc<RefCell<TreeNode>>> {
+        Solution::construct_maximum_binary_tree_loop(&nums, 0, nums.len())
+    }
+}
+
+fn main() {
+    let mut ret: usize = 0;
+    let mut nums: Vec<i32> = Vec::new();
+    for (index, arg) in env::args().enumerate() {
+        match index {
+            0 => (),
+            _ => {
+                ret += 1;
+                let number: i32 = i32::from_str(&arg).expect("Error parse.");
+                nums.push(number);
+            }
+        }
+    }
+
+    if 0 == ret {
+        println!("Require at least 1 parameter.");
+        return;
+    }
+
+    Solution::construct_maximum_binary_tree(nums);
+}