add 2110

Author: fishercoder1534

README.md

@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ ★
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                  
 |-----|----------------|---------------|--------|-------------|-------------
+|2110|[Number of Smooth Descent Periods of a Stock](https://leetcode.com/problems/number-of-smooth-descent-periods-of-a-stock/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2110.java) ||Medium||
 |2109|[Adding Spaces to a String](https://leetcode.com/problems/adding-spaces-to-a-string/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2109.java) ||Medium||
 |2108|[Find First Palindromic String in the Array](https://leetcode.com/problems/find-first-palindromic-string-in-the-array/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2108.java) ||Easy||
 |2103|[Rings and Rods](https://leetcode.com/problems/rings-and-rods/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2103.java) ||Easy||

src/main/java/com/fishercoder/solutions/_2110.java

@@ -0,0 +1,20 @@
+package com.fishercoder.solutions;
+
+public class _2110 {
+    public static class Solution1 {
+        public long getDescentPeriods(int[] prices) {
+            long ans = prices.length;
+            for (int i = 0; i < prices.length; i++) {
+                long startI = i;
+                while (i + 1 < prices.length && prices[i] - 1 == prices[i + 1]) {
+                    i++;
+                }
+                long totalNum = i - startI + 1;
+                if (totalNum > 1) {
+                    ans += ((totalNum - 1) * totalNum) / 2;
+                }
+            }
+            return ans;
+        }
+    }
+}