Add files via upload

Author: assassint2017

Number of Digit One/Number_of_Digit_One.cpp

@@ -0,0 +1,32 @@
+// 剑指上的题目
+// Runtime: 4 ms, faster than 48.35% of C++ online submissions for Number of Digit One.
+// Memory Usage: 8 MB, less than 100.00% of C++ online submissions for Number of Digit One.
+
+class Solution 
+{
+public:
+    int countDigitOne(int n) 
+    {
+        if (n <= 0)
+            return 0;
+        
+        // 同样需要注意数据溢出的问题
+        long long base = 10;
+        long long count = 0;
+        while (n / base > 0)
+            base *= 10, count++;
+        base /= 10;
+        
+        long long high = n / base;
+        long long res = 0;
+        
+        if (high == 1)
+            res += n - high * base + 1;
+        else
+            res += base;
+        
+        res += high * count * (base / 10);
+        
+        return res + countDigitOne(n - high * base);
+    }
+};

Number of Digit One/Number_of_Digit_One.py

@@ -0,0 +1,31 @@
+# Runtime: 32 ms, faster than 89.32% of Python3 online submissions for Number of Digit One.
+# Memory Usage: 13.9 MB, less than 100.00% of Python3 online submissions for Number of Digit One.
+
+class Solution:
+    def countDigitOne(self, n):
+        """
+        :type n: int
+        :rtype: int
+        """
+        
+        if n <= 0:
+            return 0
+        
+        base = 10
+        count = 0
+        while n // base > 0:
+            base *= 10
+            count += 1
+        base /= 10
+
+        high = n // base
+        res = 0
+
+        if high is 1:
+            res += n - high * base + 1
+        else:
+            res += base
+        
+        res += high * count * (base / 10)
+
+        return res + self.countDigitOne(n - high * base)