src/bin/arithmetic-slices.rs

Author: bestgopher

src/bin/arithmetic-slices.rs

@@ -0,0 +1,31 @@
+fn main() {
+    println!("{}", Solution::number_of_arithmetic_slices(vec![1, 2, 3, 4]));
+    println!("{}", Solution::number_of_arithmetic_slices(vec![1, 2, 3, 4, 5, 6]));
+    println!("{}", Solution::number_of_arithmetic_slices(vec![1, 2, 3, 4, 10, 11, 12, 13]));
+}
+
+struct Solution;
+
+impl Solution {
+    pub fn number_of_arithmetic_slices(nums: Vec<i32>) -> i32 {
+        if nums.len() < 3 { return 0; }
+
+        let mut count = 0;
+        let mut num = 2;
+        let mut s = nums[1] - nums[0];
+
+        for i in 2..nums.len() {
+            if nums[i] - nums[i - 1] == s {
+                num += 1;
+            } else {
+                if num >= 3 { count += (1..=num - 3 + 1).into_iter().sum::<i32>(); }
+                s = nums[i] - nums[i - 1];
+                num = 2;
+            }
+        }
+
+        if num >= 3 { count += (1..=num - 3 + 1).into_iter().sum::<i32>(); }
+
+        count
+    }
+}