Create 5958-number-of-smooth-descent-periods-of-a-stock.js

Author: everthis

5958-number-of-smooth-descent-periods-of-a-stock.js

@@ -0,0 +1,27 @@
+/**
+ * @param {number[]} prices
+ * @return {number}
+ */
+const getDescentPeriods = function(prices) {
+  if(prices.length === 1) return 1
+  let res = 0, idx = 0
+  
+  for (let i = 1, n = prices.length; i < n ; i++) {
+    if(prices[i - 1] - prices[i] === 1) {
+     if (i === n - 1) {
+      const len = i - idx + 1
+      res += (len + 1) * len / 2
+     }
+    } else {
+      const len = i - 1 - idx + 1
+      res += (len + 1) * len / 2
+      idx = i
+      if(i === n - 1) {
+        res += 1
+      }
+    }
+
+  }
+  
+  return res
+};