Create 1291-sequential-digits.js

Author: everthis

1291-sequential-digits.js

@@ -0,0 +1,38 @@
+/**
+ * @param {number} low
+ * @param {number} high
+ * @return {number[]}
+ */
+const sequentialDigits = function(low, high) {
+   const set = new Set()
+   let start = 0, end = 0
+   for(let i = 10; i >= 0; i--) {
+     if (low / (10 ** i) >= 1) {
+       start = ~~(low / (10 ** i))
+       break
+     }
+   }
+   for(let i = 10; i >= 0; i--) {
+     if (high / (10 ** i) >= 1) {
+       end = ~~(high / (10 ** i))
+       break
+     }
+   }
+  for(let i = 1; i <= 9; i++) {
+   helper(`${i}`)    
+  }
+
+   const res = Array.from(set)
+  res.sort((a, b) => a- b)
+  return res
+   
+  function helper(s) {
+    // console.log(s)
+    if(+s > high) return
+    if(+s >= low && +s <= high) {
+      set.add(+s)
+    }
+    if(s[s.length - 1] === '9') return
+    helper(`${s}${+s[s.length - 1] + 1}`)
+  }
+};