kt: add «3243. Shortest Distance After Road Addition Queries I»

URL:	https://leetcode.com/problems/shortest-distance-after-road-addition-queries-i/
Signed-off-by: Matej Focko <me@mfocko.xyz>

kt/shortest-distance-after-road-addition-queries-i.kt

@@ -0,0 +1,35 @@
+class Solution {
+    private fun findMinDistance(
+        n: Int,
+        graph: List<MutableList<Int>>,
+    ): Int {
+        val dp = IntArray(n)
+
+        for (u in (0..n - 2).reversed()) {
+            dp[u] = graph[u].minOfOrNull { v -> 1 + dp[v] } ?: n
+        }
+
+        return dp[0]
+    }
+
+    fun shortestDistanceAfterQueries(
+        n: Int,
+        queries: Array<IntArray>,
+    ): IntArray {
+        val distances = IntArray(queries.size)
+
+        // Construct initial graph
+        val graph = (1..n).map { mutableListOf(it) }.toList()
+        graph.last().removeLast()
+
+        // Process queries
+        for (query in queries.withIndex()) {
+            val (u, v) = query.value[0] to query.value[1]
+            graph[u].add(v)
+
+            distances[query.index] = findMinDistance(n, graph)
+        }
+
+        return distances
+    }
+}