20240317 Finished

src/problem/mod.rs

@@ -76,3 +76,4 @@ mod p2864_maximum_odd_binary_number;
 mod p2789_largest_element_in_an_array_after_merge_operations;
 mod p2312_selling_pieces_of_wood;
 mod p2684_maximum_number_of_moves_in_a_grid;
+mod p310_minimum_height_trees;

src/problem/p310_minimum_height_trees.rs

@@ -0,0 +1,83 @@
+/**
+ * [310] Minimum Height Trees
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+use std::collections::VecDeque;
+
+impl Solution {
+    pub fn find_min_height_trees(n: i32, edges: Vec<Vec<i32>>) -> Vec<i32> {
+        let n = n as usize;
+        let mut graph = vec![vec![];n];
+
+        for edge in &edges {
+            let x = edge[0] as usize;
+            let y = edge[1] as usize;
+
+            graph[x].push(y);
+            graph[y].push(x);
+        }
+
+        let mut parents = vec![usize::MAX;n];
+        let x = Solution::find_longest_node(0, &mut parents, &graph);
+        let mut y = Solution::find_longest_node(x, &mut parents, &graph);
+
+        let mut path = Vec::new();
+        parents[x] = usize::MAX;
+
+        parents = dbg!(parents);
+        while y != usize::MAX {
+            path.push(y);
+            y = parents[y];
+        }
+
+        let length = path.len();
+
+        return if length % 2 != 0 {
+            vec![path[length / 2] as i32]
+        } else {
+            vec![path[length / 2 - 1] as i32, path[length / 2] as i32]
+        };
+    }
+
+    fn find_longest_node(node: usize, parents: &mut Vec<usize>, graph: &Vec<Vec<usize>>) -> usize {
+        let n = graph.len();
+
+        let mut queue = VecDeque::with_capacity(n);
+        let mut visited = vec![false;n];
+
+        queue.push_back(node);
+        visited[node] = true;
+        let mut result = usize::MAX;
+
+        while !queue.is_empty() {
+            let now = queue.pop_front().unwrap();
+            dbg!(now);
+            result = now;
+            for next in &graph[now] {
+                let next = *next;
+                if !visited[next] {
+                    visited[next] = true;
+                    parents[next] = now;
+                    queue.push_back(next);
+                }
+            }
+        } 
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_310() {
+        assert_eq!(vec![1], Solution::find_min_height_trees(4, vec![vec![1,0], vec![1,2], vec![1,3]]));
+    }
+}