feat(cpp): add josephus_optimized.cpp

Author: ongshunping

cpp/Math and Geometry/josephus_optimized.cpp

@@ -0,0 +1,8 @@
+int josephusOptimized(int n, int k) {
+    int res = 0;
+    for (int i = 2; i <= n; i++) {
+        // res[i] = (res[i - 1] + k) % i;
+        res = (res + k) % i;
+    }
+    return res;
+}