1615. Maximal Network Rank: AC

Author: tan-wei

src/solution/mod.rs

@@ -1217,3 +1217,4 @@ mod s1609_even_odd_tree;
 mod s1610_maximum_number_of_visible_points;
 mod s1611_minimum_one_bit_operations_to_make_integers_zero;
 mod s1614_maximum_nesting_depth_of_the_parentheses;
+mod s1615_maximal_network_rank;

src/solution/s1615_maximal_network_rank.rs

@@ -0,0 +1,120 @@
+/**
+ * [1615] Maximal Network Rank
+ *
+ * There is an infrastructure of n cities with some number of roads connecting these cities. Each roads[i] = [ai, bi] indicates that there is a bidirectional road between cities ai and bi.
+ * The network rank of two different cities is defined as the total number of directly connected roads to either city. If a road is directly connected to both cities, it is only counted once.
+ * The maximal network rank of the infrastructure is the maximum network rank of all pairs of different cities.
+ * Given the integer n and the array roads, return the maximal network rank of the entire infrastructure.
+ *  
+ * Example 1:
+ * <img alt="" src="https://assets.leetcode.com/uploads/2020/09/21/ex1.png" style="width: 292px; height: 172px;" />
+ *
+ * Input: n = 4, roads = [[0,1],[0,3],[1,2],[1,3]]
+ * Output: 4
+ * Explanation: The network rank of cities 0 and 1 is 4 as there are 4 roads that are connected to either 0 or 1. The road between 0 and 1 is only counted once.
+ *
+ * Example 2:
+ * <img alt="" src="https://assets.leetcode.com/uploads/2020/09/21/ex2.png" style="width: 292px; height: 172px;" />
+ *
+ * Input: n = 5, roads = [[0,1],[0,3],[1,2],[1,3],[2,3],[2,4]]
+ * Output: 5
+ * Explanation: There are 5 roads that are connected to cities 1 or 2.
+ *
+ * Example 3:
+ *
+ * Input: n = 8, roads = [[0,1],[1,2],[2,3],[2,4],[5,6],[5,7]]
+ * Output: 5
+ * Explanation: The network rank of 2 and 5 is 5. Notice that all the cities do not have to be connected.
+ *
+ *  
+ * Constraints:
+ *
+ * 	2 <= n <= 100
+ * 	0 <= roads.length <= n * (n - 1) / 2
+ * 	roads[i].length == 2
+ * 	0 <= ai, bi <= n-1
+ * 	ai != bi
+ * 	Each pair of cities has at most one road connecting them.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/maximal-network-rank/
+// discuss: https://leetcode.com/problems/maximal-network-rank/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn maximal_network_rank(n: i32, roads: Vec<Vec<i32>>) -> i32 {
+        let n = n as usize;
+        let mut degree = vec![std::collections::HashSet::new(); n];
+        for v in roads {
+            degree[v[0] as usize].insert(v[1] as usize);
+            degree[v[1] as usize].insert(v[0] as usize);
+        }
+
+        let mut result = 0;
+
+        for i in 0..n - 1 {
+            for j in i + 1..n {
+                let mut tmp = degree[i].len() + degree[j].len();
+                if degree[i].contains(&j) {
+                    tmp -= 1;
+                }
+                result = result.max(tmp);
+            }
+        }
+
+        result as i32
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1615_example_1() {
+        let n = 4;
+        let roads = vec![vec![0, 1], vec![0, 3], vec![1, 2], vec![1, 3]];
+
+        let result = 4;
+
+        assert_eq!(Solution::maximal_network_rank(n, roads), result);
+    }
+
+    #[test]
+    fn test_1615_example_2() {
+        let n = 5;
+        let roads = vec![
+            vec![0, 1],
+            vec![0, 3],
+            vec![1, 2],
+            vec![1, 3],
+            vec![2, 3],
+            vec![2, 4],
+        ];
+
+        let result = 5;
+
+        assert_eq!(Solution::maximal_network_rank(n, roads), result);
+    }
+
+    fn test_1615_example_3() {
+        let n = 8;
+        let roads = vec![
+            vec![0, 1],
+            vec![1, 2],
+            vec![2, 3],
+            vec![2, 4],
+            vec![5, 6],
+            vec![5, 7],
+        ];
+
+        let result = 5;
+
+        assert_eq!(Solution::maximal_network_rank(n, roads), result);
+    }
+}