Create 2999-count-the-number-of-powerful-integers.js

Author: everthis

2999-count-the-number-of-powerful-integers.js

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+/**
+ * @param {number} num
+ * @param {number} limit
+ * @param {string} s
+ */
+function adjust(num, limit, s) {
+  let sn = parseInt(s);
+  let sufMod = 10 ** s.length;
+
+  let suf = num % sufMod;
+  num = Math.floor(num / sufMod);
+  if (suf < sn) --num;
+
+  if (num <= 0) return num + 1;
+
+  let sNum = num.toString();
+  let res = sNum.charCodeAt(0) - 48;
+  let tight = 1;
+  if (res > limit) {
+    return (limit + 1) ** sNum.length;
+  }
+  
+  for (let i = 1; i < sNum.length; ++i) {
+    res *= (limit + 1);
+    
+    if (tight) {
+      let c = sNum.charCodeAt(i) - 48;
+      if (c > limit) {
+        tight = 0;
+        res += limit + 1;
+      }
+      else {
+        res += c;
+      }
+    }
+  }
+
+  return res + tight;
+}
+/**
+ * @param {number} start
+ * @param {number} finish
+ * @param {number} limit
+ * @param {string} s
+ * @return {number}
+ */
+var numberOfPowerfulInt = function (start, finish, limit, s) {
+  --start;
+
+  let ss = adjust(start, limit, s);
+  let ff = adjust(finish, limit, s);
+
+  return ff - ss;
+};