1791. Find Center of Star Graph: AC

src/solution/mod.rs

@@ -1349,3 +1349,4 @@ mod s1785_minimum_elements_to_add_to_form_a_given_sum;
 mod s1786_number_of_restricted_paths_from_first_to_last_node;
 mod s1787_make_the_xor_of_all_segments_equal_to_zero;
 mod s1790_check_if_one_string_swap_can_make_strings_equal;
+mod s1791_find_center_of_star_graph;

src/solution/s1791_find_center_of_star_graph.rs

@@ -0,0 +1,69 @@
+/**
+ * [1791] Find Center of Star Graph
+ *
+ * There is an undirected star graph consisting of n nodes labeled from 1 to n. A star graph is a graph where there is one center node and exactly n - 1 edges that connect the center node with every other node.
+ * You are given a 2D integer array edges where each edges[i] = [ui, vi] indicates that there is an edge between the nodes ui and vi. Return the center of the given star graph.
+ *  
+ * Example 1:
+ * <img alt="" src="https://assets.leetcode.com/uploads/2021/02/24/star_graph.png" style="width: 331px; height: 321px;" />
+ * Input: edges = [[1,2],[2,3],[4,2]]
+ * Output: 2
+ * Explanation: As shown in the figure above, node 2 is connected to every other node, so 2 is the center.
+ *
+ * Example 2:
+ *
+ * Input: edges = [[1,2],[5,1],[1,3],[1,4]]
+ * Output: 1
+ *
+ *  
+ * Constraints:
+ *
+ * 	3 <= n <= 10^5
+ * 	edges.length == n - 1
+ * 	edges[i].length == 2
+ * 	1 <= ui, vi <= n
+ * 	ui != vi
+ * 	The given edges represent a valid star graph.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/find-center-of-star-graph/
+// discuss: https://leetcode.com/problems/find-center-of-star-graph/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn find_center(edges: Vec<Vec<i32>>) -> i32 {
+        if let Some(x) = edges[1].iter().position(|x| *x == edges[0][0]) {
+            edges[1][x]
+        } else {
+            edges[0][1]
+        }
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1791_example_1() {
+        let edges = vec![vec![1, 2], vec![2, 3], vec![4, 2]];
+
+        let result = 2;
+
+        assert_eq!(Solution::find_center(edges), result);
+    }
+
+    #[test]
+    fn test_1791_example_2() {
+        let edges = vec![vec![1, 2], vec![5, 1], vec![1, 3], vec![1, 4]];
+
+        let result = 1;
+
+        assert_eq!(Solution::find_center(edges), result);
+    }
+}