diff --git a/array/fast_slow_pointer_26/src/main.rs b/array/fast_slow_pointer_26/src/main.rs
index b2eb06c..bf83344 100644
--- a/array/fast_slow_pointer_26/src/main.rs
+++ b/array/fast_slow_pointer_26/src/main.rs
@@ -1,8 +1,25 @@
 fn main() {
-    println!("Hello, world!");
+    let mut case_a: Vec<i32> = vec![3, 2, 2, 3];
+    // 傳入時也要帖別聲明 &mut -> &mut case_a
+    let result = remove_duplicates(&mut case_a, 3);
+    println!("Result: {}", result);
 }
 
 pub fn remove_duplicates(nums: &mut Vec<i32>) -> i32 {
-    let mut slow_pointer :usize= 0;
-    let mut fast_pointer:usize=0;
+    let mut fast_pointer:usize = 0;
+    let mut slow_pointer:usize = 0;
+    let stop = nums.len();
+    let mut target = nums[0];
+
+    // [), 想停止條件
+    while fast_pointer < stop {
+        if nums[fast_pointer] != target {
+            nums[slow_pointer] = nums[fast_pointer];
+            slow_pointer += 1;
+            target = nums[fast_pointer]
+        }
+        fast_pointer +=1;
+    }
+
+    return slow_pointer as i32
 }
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