diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index c1ddddd..fb72952 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -536,3 +536,5 @@ mod p2012_sum_of_beauty_in_the_array;
 mod p3305_count_of_substrings_containing_every_vowel_and_k_consonants_i;
 
 mod p3306_count_of_substrings_containing_every_vowel_and_k_consonants_ii;
+
+mod p3340_check_balanced_string;
diff --git a/src/problem/p3340_check_balanced_string.rs b/src/problem/p3340_check_balanced_string.rs
new file mode 100644
index 0000000..cbc54e7
--- /dev/null
+++ b/src/problem/p3340_check_balanced_string.rs
@@ -0,0 +1,27 @@
+/**
+ * [3340] Check Balanced String
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn is_balanced(num: String) -> bool {
+        let num: Vec<i32> = num.bytes().map(|x| (x - b'0') as i32).collect();
+
+        num.iter().step_by(2).sum::<i32>() == num.iter().skip(1).step_by(2).sum::<i32>()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_3340() {
+        assert!(!Solution::is_balanced("1234".to_owned()));
+        assert!(Solution::is_balanced("24123".to_owned()));
+    }
+}