feat: add question 233

Author: yinxin630

233.数字-1-的个数.js

@@ -0,0 +1,21 @@
+/*
+ * @lc app=leetcode.cn id=233 lang=javascript
+ *
+ * [233] 数字 1 的个数
+ */
+
+// @lc code=start
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var countDigitOne = function(n) {
+    let result = 0;
+    for (let i = 1; i <= n; i *= 10) {
+        const div = i * 10;
+        result += Math.floor(n / div) * i + Math.min(Math.max(n % div - i + 1, 0), i);
+    }
+
+    return result;
+};
+// @lc code=end