complete 3425.c 27569.kt

storage/zeta/kt/completed/27569.kt

@@ -0,0 +1,28 @@
+import kotlin.math.log10
+import kotlin.math.pow
+
+fun champernowneCount(n: Long, k: Long): Int {
+    // f(1) = 1,
+    // f(2) = f(1) * 10 + 2,
+    // f(10) = f(9) * 100 + 10,
+    // f(100) = f(99) * 1000 + 100,
+
+    var beforeChamps = 0L
+
+    var cnt = 0
+    for (i in 1..n) {
+        val logged = (log10(i.toDouble()) + 1).toInt()
+
+        val x = (beforeChamps * 10.0.pow(logged).toLong() + i) % k
+        beforeChamps = x
+        if (x == 0L) cnt++
+    }
+
+    return cnt
+}
+
+fun main() = with(System.`in`.bufferedReader()) {
+    val (n, k) = this.readLine().split(" ").map { it.toLong() }
+
+    println(champernowneCount(n, k))
+}