solve(programmers): LV2_181187_두 원 사이의 정수 쌍_kt

src/programmers/level_1/수학/두_원_사이의_정수_쌍.kt

@@ -0,0 +1,21 @@
+package programmers.level_1.수학
+
+import kotlin.math.ceil
+import kotlin.math.floor
+import kotlin.math.sqrt
+
+class 두_원_사이의_정수_쌍 {
+    fun solution(r1: Int, r2: Int): Long {
+        var answer: Long = 0
+        val r22 = r2.toLong() * r2.toLong()
+        val r11 = r1.toLong() * r1.toLong()
+
+        for (x in 1..r2) {
+            val biy = floor(sqrt((r22 - x.toLong() * x).toDouble())).toLong()
+            val sy = if (x >= r1) 0 else ceil(sqrt((r11 - x.toLong() * x).toDouble())).toLong()
+            answer += biy - sy + 1
+        }
+
+        return answer * 4
+    }
+}