1761. Minimum Degree of a Connected Trio in a Graph: RETRY, credit: https://leetcode.com/problems/minimum-degree-of-a-connected-trio-in-a-graph/solutions/3209233/just-a-runnable-solution/

Author: tan-wei

src/solution/mod.rs

@@ -1327,3 +1327,4 @@ mod s1755_closest_subsequence_sum;
 mod s1758_minimum_changes_to_make_alternating_binary_string;
 mod s1759_count_number_of_homogenous_substrings;
 mod s1760_minimum_limit_of_balls_in_a_bag;
+mod s1761_minimum_degree_of_a_connected_trio_in_a_graph;

src/solution/s1761_minimum_degree_of_a_connected_trio_in_a_graph.rs

@@ -0,0 +1,117 @@
+/**
+ * [1761] Minimum Degree of a Connected Trio in a Graph
+ *
+ * You are given an undirected graph. You are given an integer n which is the number of nodes in the graph and an array edges, where each edges[i] = [ui, vi] indicates that there is an undirected edge between ui and vi.
+ * A connected trio is a set of three nodes where there is an edge between every pair of them.
+ * The degree of a connected trio is the number of edges where one endpoint is in the trio, and the other is not.
+ * Return the minimum degree of a connected trio in the graph, or -1 if the graph has no connected trios.
+ *  
+ * Example 1:
+ * <img alt="" src="https://assets.leetcode.com/uploads/2021/01/26/trios1.png" style="width: 388px; height: 164px;" />
+ * Input: n = 6, edges = [[1,2],[1,3],[3,2],[4,1],[5,2],[3,6]]
+ * Output: 3
+ * Explanation: There is exactly one trio, which is [1,2,3]. The edges that form its degree are bolded in the figure above.
+ *
+ * Example 2:
+ * <img alt="" src="https://assets.leetcode.com/uploads/2021/01/26/trios2.png" style="width: 388px; height: 164px;" />
+ * Input: n = 7, edges = [[1,3],[4,1],[4,3],[2,5],[5,6],[6,7],[7,5],[2,6]]
+ * Output: 0
+ * Explanation: There are exactly three trios:
+ * 1) [1,4,3] with degree 0.
+ * 2) [2,5,6] with degree 2.
+ * 3) [5,6,7] with degree 2.
+ *
+ *  
+ * Constraints:
+ *
+ * 	2 <= n <= 400
+ * 	edges[i].length == 2
+ * 	1 <= edges.length <= n * (n-1) / 2
+ * 	1 <= ui, vi <= n
+ * 	ui != vi
+ * 	There are no repeated edges.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/minimum-degree-of-a-connected-trio-in-a-graph/
+// discuss: https://leetcode.com/problems/minimum-degree-of-a-connected-trio-in-a-graph/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    // Credit: https://leetcode.com/problems/minimum-degree-of-a-connected-trio-in-a-graph/solutions/3209233/just-a-runnable-solution/
+    pub fn min_trio_degree(n: i32, edges: Vec<Vec<i32>>) -> i32 {
+        let n = n as usize;
+        let mut al = vec![vec![]; n + 1];
+        let mut cnt = vec![0; n + 1];
+        let mut result = std::i32::MAX;
+
+        for e in edges.iter() {
+            let t1 = e[0].min(e[1]) as usize;
+            let t2 = e[0].max(e[1]) as usize;
+            al[t1].push(t2);
+            cnt[t1] += 1;
+            cnt[t2] += 1;
+        }
+
+        for t1 in 1..=n {
+            for &t2 in al[t1].iter() {
+                for &t3 in al[t1].iter() {
+                    if t2 < t3 && al[t2].contains(&t3) {
+                        result = result.min(cnt[t1] + cnt[t2] + cnt[t3] - 6);
+                    }
+                }
+            }
+        }
+
+        if result == std::i32::MAX {
+            -1
+        } else {
+            result
+        }
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1761_example_1() {
+        let n = 6;
+        let edges = vec![
+            vec![1, 2],
+            vec![1, 3],
+            vec![3, 2],
+            vec![4, 1],
+            vec![5, 2],
+            vec![3, 6],
+        ];
+
+        let result = 3;
+
+        assert_eq!(Solution::min_trio_degree(n, edges), result);
+    }
+
+    #[test]
+    fn test_1761_example_2() {
+        let n = 7;
+        let edges = vec![
+            vec![1, 3],
+            vec![4, 1],
+            vec![4, 3],
+            vec![2, 5],
+            vec![5, 6],
+            vec![6, 7],
+            vec![7, 5],
+            vec![2, 6],
+        ];
+
+        let result = 0;
+
+        assert_eq!(Solution::min_trio_degree(n, edges), result);
+    }
+}