diff --git a/src/algorithm/inversion_number.rs b/src/algorithm/inversion_number.rs
index 4430ce6..57c6406 100644
--- a/src/algorithm/inversion_number.rs
+++ b/src/algorithm/inversion_number.rs
@@ -1,8 +1,8 @@
 //! 転倒数
-pub fn inversion_number(array: &[i64]) -> i64 {
+pub fn inversion_number<T: Copy + PartialOrd>(array: &[T]) -> i64 {
     count_merge(&mut array.to_vec(), 0..array.len())
 }
-fn count_merge(array: &mut Vec<i64>, range: std::ops::Range<usize>) -> i64 {
+fn count_merge<T: Copy + PartialOrd>(array: &mut Vec<T>, range: std::ops::Range<usize>) -> i64 {
     let length = range.len() as i64;
     if length <= 1 {
         return 0;