diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index 2e65742..dc334c2 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -294,3 +294,5 @@ mod p3259_maximum_energy_boost_from_two_drinks;
 mod p3226_number_of_bit_changes_to_make_two_integers_equal;
 
 mod p638_shopping_offers;
+
+mod p633_sum_of_square_numbers;
diff --git a/src/problem/p633_sum_of_square_numbers.rs b/src/problem/p633_sum_of_square_numbers.rs
new file mode 100644
index 0000000..5c9a56d
--- /dev/null
+++ b/src/problem/p633_sum_of_square_numbers.rs
@@ -0,0 +1,44 @@
+/**
+ * [633] Sum of Square Numbers
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn judge_square_sum(c: i32) -> bool {
+        use std::collections::HashSet;
+
+        let mut set = HashSet::new();
+        let mut i = 0i64;
+        let c = c as i64;
+
+        while i.pow(2) <= c {
+            let value = c - i.pow(2);
+
+            set.insert(i.pow(2));
+            if set.contains(&value) {
+                return true;
+            }
+
+            i += 1;
+        }
+
+        false
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_633() {
+        assert!(Solution::judge_square_sum(5));
+        assert!(Solution::judge_square_sum(4));
+        assert!(!Solution::judge_square_sum(3));
+        assert!(Solution::judge_square_sum(2));
+    }
+}