6.17 : math(멍멍이 쓰다듬기)

baekjoon/1669.js

@@ -0,0 +1,45 @@
+// 멍멍이 쓰다듬기 : 수학
+const [monkey, dog] = require("fs")
+  .readFileSync("/dev/stdin")
+  .toString()
+  .trim()
+  .split(" ")
+  .map((v) => Number(v));
+const diff = dog - monkey;
+
+if (diff === 0) {
+  console.log(0);
+} else {
+  const sqrt = Math.sqrt(diff);
+  const curr = Math.pow(Math.floor(sqrt), 2);
+  if (sqrt % 1 === 0) {
+    console.log(2 * sqrt - 1);
+  } else {
+    const next = Math.pow(Math.floor(sqrt) + 1, 2);
+    if ((curr + next) / 2 < diff) {
+      console.log(Math.floor(sqrt) * 2 + 1);
+    } else {
+      console.log(Math.floor(sqrt) * 2);
+    }
+  }
+}
+
+// 0 => 0
+// 1 => 1 (1)
+// 2 => 11 (2)
+// 3 => 111 (3)
+// 4 => 121 (3)
+// 5 => 1211 (4)
+// 6 => 1221 (4)
+// 7 => 12121 (5)
+// 8 => 12221 (5)
+// 9 => 12321 (5)
+// 10 => 6
+// 11 => 6
+// 12 => 6
+// 13 => 7
+// 14 => 7
+// 15 => 7
+// 16 => 1234321 (7)
+
+// Fly me to the Alpha Centauri(1011) 문제와 똑같은 문제