update sungkohan

storage/sungkohan/kt/completed/2025-div2-E.kt

@@ -0,0 +1,49 @@
+import java.util.Stack
+
+fun countNearestFarRelation(n: Int, edges: Array<MutableList<Pair<Int, Int>>>): Long {
+    val originXor = IntArray(n)
+
+    val deq = Stack<Pair<Int, Int>>()
+    deq.add(0 to 0)
+    while (deq.isNotEmpty()) {
+        val (now, before) = deq.pop()
+
+        for ((nxt, w) in edges[now]) {
+            if (nxt == before) {
+                continue
+            } else {
+                originXor[nxt] = originXor[now] xor w
+                deq.add(nxt to now)
+            }
+        }
+    }
+    originXor.sort()
+    var cnt: Long = 0
+    var before = -1
+    var cntSliced: Long = 0
+    for (i in originXor) {
+        if (i == before) {
+            cntSliced++
+        } else {
+            cnt += (cntSliced) * (cntSliced - 1) / 2
+            before = i
+            cntSliced = 1
+        }
+    }
+    cnt += (cntSliced) * (cntSliced - 1) / 2
+
+    return cnt
+}
+
+fun main() = with(System.`in`.bufferedReader()) {
+    val n = this.readLine().toInt()
+    var edges: Array<MutableList<Pair<Int, Int>>> = Array(n + 1) { mutableListOf() }
+    for (i in 0 until (n - 1)) {
+        val (u, v, w) = this.readLine().split(" ").map { it.toInt() }
+        edges[u - 1].add(v - 1 to w)
+        edges[v - 1].add(u - 1 to w)
+    }
+
+    println(countNearestFarRelation(n, edges))
+
+}