Create alternating-digit-sum.cpp

kamyu104 · Jan 24, 2023 · 00f4cb5 · 00f4cb5
1 parent d08966f
commit 00f4cb5
Showing 1 changed file with 15 additions and 0 deletions.
diff --git a/C++/alternating-digit-sum.cpp b/C++/alternating-digit-sum.cpp
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+// Time:  O(logn)
+// Space: O(1)
+
+// math
+class Solution {
+public:
+    int alternateDigitSum(int n) {
+        int result = 0, sign = 1;
+        for (; n; n /= 10) {
+            sign *= -1;
+            result += sign * (n % 10);
+        }
+        return sign * result;
+    }
+};