solve #129

Author: aylei

src/lib.rs

@@ -127,3 +127,4 @@ mod n0125_valid_palindrome;
 mod n0126_word_ladder_ii;
 mod n0127_word_ladder;
 mod n0128_longest_consecutive_sequence;
+mod n0129_sum_root_to_leaf_numbers;

src/n0129_sum_root_to_leaf_numbers.rs

@@ -0,0 +1,82 @@
+/**
+ * [129] Sum Root to Leaf Numbers
+ *
+ * Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.
+ * 
+ * An example is the root-to-leaf path 1->2->3 which represents the number 123.
+ * 
+ * Find the total sum of all root-to-leaf numbers.
+ * 
+ * Note: A leaf is a node with no children.
+ * 
+ * Example:
+ * 
+ * 
+ * Input: [1,2,3]
+ *     1
+ *    / \
+ *   2   3
+ * Output: 25
+ * Explanation:
+ * The root-to-leaf path 1->2 represents the number 12.
+ * The root-to-leaf path 1->3 represents the number 13.
+ * Therefore, sum = 12 + 13 = 25.
+ * 
+ * Example 2:
+ * 
+ * 
+ * Input: [4,9,0,5,1]
+ *     4
+ *    / \
+ *   9   0
+ *  / \
+ * 5   1
+ * Output: 1026
+ * Explanation:
+ * The root-to-leaf path 4->9->5 represents the number 495.
+ * The root-to-leaf path 4->9->1 represents the number 491.
+ * The root-to-leaf path 4->0 represents the number 40.
+ * Therefore, sum = 495 + 491 + 40 = 1026.
+ * 
+ */
+pub struct Solution {}
+use super::util::tree::{TreeNode, to_tree};
+
+// submission codes start here
+
+use std::rc::Rc;
+use std::cell::RefCell;
+use std::collections::VecDeque;
+impl Solution {
+    pub fn sum_numbers(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        let mut sum = 0;
+        if root.is_none() { return sum }
+        let mut deq = VecDeque::new();
+        deq.push_back((root.clone(), 0));
+        while let Some(item) = deq.pop_front() {
+            if let (Some(node), acc)  = item {
+                let acc = acc * 10 + node.borrow().val;
+                if node.borrow().left.is_none() && node.borrow().right.is_none() {
+                    sum += acc;
+                    continue;
+                }
+                deq.push_back((node.borrow().left.clone(), acc));
+                deq.push_back((node.borrow().right.clone(), acc));
+            }
+        }
+        sum
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_129() {
+        assert_eq!(Solution::sum_numbers(tree![1,2,3]), 25);
+        assert_eq!(Solution::sum_numbers(tree![4,9,0,5,1]), 1026);
+    }
+}