@@ -574,66 +574,48 @@ object Solution {
574574rust:
575575``` rust
576576impl Solution {
577- pub fn min_depth (root : Option <Rc <RefCell <TreeNode >>>) -> i32 {
578- return Solution :: bfs (root )
579- }
580- 581577 // 递归
582- pub fn dfs (node : Option <Rc <RefCell <TreeNode >>>) -> i32 {
583- if node . is_none (){
584- return 0 ;
585- }
586- let parent = node . unwrap ();
587- let left_child = parent . borrow_mut (). left. take ();
588- let right_child = parent . borrow_mut (). right. take ();
589- if left_child . is_none () && right_child . is_none (){
590- return 1 ;
591- }
592- let mut min_depth = i32 :: MAX ;
593- if left_child . is_some (){
594- let left_depth = Solution :: dfs (left_child );
595- if left_depth <= min_depth {
596- min_depth = left_depth
597- }
598- }
599- if right_child . is_some (){
600- let right_depth = Solution :: dfs (right_child );
601- if right_depth <= min_depth {
602- min_depth = right_depth
578+ pub fn min_depth (root : Option <Rc <RefCell <TreeNode >>>) -> i32 {
579+ if let Some (node ) = root {
580+ match (node . borrow (). left. clone (), node . borrow (). right. clone ()) {
581+ (Some (n1 ), None ) => 1 + Self :: min_depth (Some (n1 )),
582+ (None , Some (n2 )) => 1 + Self :: min_depth (Some (n2 )),
583+ (Some (n1 ), Some (n2 )) => {
584+ 1 + std :: cmp :: min (Self :: min_depth (Some (n1 )), Self :: min_depth (Some (n2 )))
585+ }
586+ _ => 1 ,
603587 }
588+ } else {
589+ 0
604590 }
605- min_depth + 1
606- 607591 }
608592
609593 // 迭代
610- pub fn bfs (node : Option <Rc <RefCell <TreeNode >>>) -> i32 {
611- let mut min_depth = 0 ;
612- if node . is_none (){
613- return min_depth
594+ // 需要 use std::collections::VecDeque;
595+ pub fn min_depth (root : Option <Rc <RefCell <TreeNode >>>) -> i32 {
596+ let mut res = 0 ;
597+ let mut queue = VecDeque :: new ();
598+ if root . is_some () {
599+ queue . push_back (root );
614600 }
615- let mut stack = vec! [node . unwrap ()];
616- while ! stack . is_empty (){
617- min_depth += 1 ;
618- let num = stack . len ();
619- for _i in 0 .. num {
620- let top = stack . remove (0 );
621- let left_child = top . borrow_mut (). left. take ();
622- let right_child = top . borrow_mut (). right. take ();
623- if left_child . is_none () && right_child . is_none (){
624- return min_depth ;
601+ while ! queue . is_empty () {
602+ res += 1 ;
603+ for _ in 0 .. queue . len () {
604+ let node = queue . pop_front (). unwrap (). unwrap ();
605+ if node . borrow (). left. is_none () && node . borrow (). right. is_none () {
606+ return res ;
625607 }
626- if left_child . is_some (){
627- stack . push ( left_child . unwrap ());
608+ if node . borrow () . left . is_some (){
609+ queue . push_back ( node . borrow () . left . clone ());
628610 }
629- if right_child . is_some (){
630- stack . push ( right_child . unwrap ());
611+ if node . borrow () . right . is_some (){
612+ queue . push_back ( node . borrow () . right . clone ());
631613 }
632614 }
633615 }
634- min_depth
616+ res
635617 }
636- 618+ }
637619```
638620
639621<p align =" center " >
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