diff --git a/hyeontaek/ValidPerfectSquare.java b/hyeontaek/ValidPerfectSquare.java
new file mode 100644
index 0000000..e573474
--- /dev/null
+++ b/hyeontaek/ValidPerfectSquare.java
@@ -0,0 +1,29 @@
+package hyeontaek;
+
+public class ValidPerfectSquare {
+
+  public static boolean isPerfectSquare(int num) {
+    if (num < 2) {
+      return true;
+    }
+    long left = 2, right = num / 2, mid, square;
+    while (left <= right) {
+      mid = left + (right - left) / 2;
+      square = mid * mid;
+      if (square == num) {
+        return true;
+      } else if (square > num) {
+        right = mid - 1;
+      } else {
+        left = mid + 1;
+      }
+    }
+    return false;
+  }
+
+  public static void main(String[] args) {
+    System.out.println(isPerfectSquare(16));
+    System.out.println(isPerfectSquare(14));
+  }
+
+}