20240609 Finished

src/problem/mod.rs

@@ -144,3 +144,4 @@ mod p100_same_tree;
 mod p226_invert_binary_tree;
 mod p101_symmetric_tree;
 mod p114_flatten_binary_tree_to_linked_list;
+mod p112_path_sum;

src/problem/p112_path_sum.rs

@@ -0,0 +1,71 @@
+/**
+ * [112] Path Sum
+ */
+pub struct Solution {}
+
+use crate::util::tree::{TreeNode, to_tree};
+
+// submission codes start here
+
+// Definition for a binary tree node.
+// #[derive(Debug, PartialEq, Eq)]
+// pub struct TreeNode {
+//   pub val: i32,
+//   pub left: Option<Rc<RefCell<TreeNode>>>,
+//   pub right: Option<Rc<RefCell<TreeNode>>>,
+// }
+//
+// impl TreeNode {
+//   #[inline]
+//   pub fn new(val: i32) -> Self {
+//     TreeNode {
+//       val,
+//       left: None,
+//       right: None
+//     }
+//   }
+// }
+use std::rc::Rc;
+use std::cell::RefCell;
+impl Solution {
+    fn dfs(node: &Rc<RefCell<TreeNode>>, current_sum: i32, target_sum: i32) -> bool {
+        // 到达叶子节点
+        if node.borrow().left.is_none() && node.borrow().right.is_none() {
+            return current_sum + node.borrow().val == target_sum;
+        }
+
+        if let Some(left) = &node.borrow().left {
+            if Self::dfs(left, current_sum + node.borrow().val, target_sum) {
+                return true;
+            }
+        }
+
+        if let Some(right) = &node.borrow().right {
+            if Self::dfs(right, current_sum + node.borrow().val, target_sum) {
+                return true;
+            }
+        }
+
+        false
+    }
+
+
+    pub fn has_path_sum(root: Option<Rc<RefCell<TreeNode>>>, target_sum: i32) -> bool {
+        if let Some(root) = root {
+            return Self::dfs(&root, 0, target_sum);
+        }
+
+        false
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_112() {
+    }
+}