feat: medium: find_closest_node_to_given_two_nodes.rs

Author: illiafox

src/medium/find_closest_node_to_given_two_nodes.rs

@@ -0,0 +1,63 @@
+struct Solution;
+
+impl Solution {
+    fn traverse(edges: &[i32], start_node: usize) -> Vec<i32> {
+        let mut distances = vec![-1; edges.len()];
+        let mut current = start_node;
+        let mut distance = 0;
+
+        while distances[current] == -1 {
+            distances[current] = distance;
+            let idx = edges[current];
+            if idx == -1 {
+                break;
+            }
+            current = idx as usize;
+            distance += 1;
+        }
+
+        distances
+    }
+
+    // https://leetcode.com/problems/find-closest-node-to-given-two-nodes
+    // I am doing this again...
+    pub fn closest_meeting_node(edges: Vec<i32>, node1: i32, node2: i32) -> i32 {
+        let node1_distances = Self::traverse(&edges, node1 as usize);
+        let node2_distances = Self::traverse(&edges, node2 as usize);
+
+        let mut candidate: i32 = -1;
+        let mut min_distance = i32::MAX;
+
+        for i in 0..edges.len() {
+            if node1_distances[i] == -1 || node2_distances[i] == -1 {
+                continue;
+            }
+
+            let distance = node2_distances[i].max(node1_distances[i]);
+            if distance < min_distance {
+                candidate = i as i32;
+                min_distance = distance;
+            }
+        }
+
+        candidate
+    }
+}
+
+#[test]
+fn test() {
+    let test_cases = vec![
+        (vec![2, 2, 3, -1], 0, 1, 2),
+        (vec![1, 2, -1], 0, 2, 2),
+        (vec![4, 4, 4, 5, 1, 2, 2], 1, 1, 1),
+        (vec![5, 3, 1, 0, 2, 4, 5], 3, 2, 3),
+    ];
+
+    for (edges, node1, node2, expected) in test_cases {
+        assert_eq!(
+            Solution::closest_meeting_node(edges.clone(), node1, node2),
+            expected,
+            "closest_meeting_node: failed for edges: {edges:?}, node1 {node1} node2 {node2}",
+        );
+    }
+}

src/medium/mod.rs

@@ -16,6 +16,7 @@ mod design_a_number_container_system;
 mod distant_barcodes;
 mod domino_and_tromino_tiling;
 mod evaluate_reverse_polish_notation;
+mod find_closest_node_to_given_two_nodes;
 mod find_eventual_safe_states;
 mod find_peak_element;
 mod find_the_number_of_distinct_colors_among_the_balls;