diff --git a/src/main.rs b/src/main.rs
index 458dfb5..9b2d341 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,28 +2,17 @@ mod arr;
 struct Solution {}
 
 impl Solution {
-    pub fn triangle_number(nums: Vec<i32>) -> i32 {
-        if nums.len() < 3 {
-            return 0;
-        }
-        let mut nums = nums;
-        nums.sort();
-        let mut ans = 0;
-        for i in 0..nums.len() - 2 {
-            let mut r = i + 2;
-            for l in i + 1..nums.len() - 1 {
-                while r < nums.len() && nums[i] + nums[l] > nums[r] {
-                    r += 1;
-                }
-
-                ans += ((r - l) as i32 - 1).max(0);
+    pub fn triangular_sum(mut nums: Vec<i32>) -> i32 {
+        for i in 0.. nums.len() - 1 {
+            for j in 0..nums.len() - 1 - i {
+                nums[j] = (nums[j] + nums[j + 1]) % 10;
             }
         }
-        ans
+        nums[0]
     }
 }
 
 fn main() {
-    let arr = vec![7, 0, 0, 0];
-    println!("{}", Solution::triangle_number(arr));
+    let arr = vec![1,2,3,4,5];
+    println!("{}", Solution::triangular_sum(arr));
 }