Initial commit

1 files changed, 34 insertions, 0 deletions

diff --git a/07_mathematics/counting_divisors_1713.cpp b/07_mathematics/counting_divisors_1713.cpp
new file mode 100644
index 0000000..fe30ab4
--- /dev/null
+++ b/07_mathematics/counting_divisors_1713.cpp
@@ -0,0 +1,34 @@
+#include <array>
+#include <iostream>
+
+constexpr size_t max = 1000001;
+std::array<size_t, max> spf; // Smallest prime factor of i
+
+size_t ndiv(size_t x) {
+        size_t n{1}, d{0}, e{0};
+        for (size_t i = x; i > 1; i /= spf[i]) {
+                if (spf[i] != d) {
+                        n *= e+1;
+                        d = spf[i];
+                        e = 1;
+                } else e++;
+        }
+        return n * (e+1);
+}
+
+int main() {
+        for (size_t i = 2; i < max; i++) {
+                if (spf[i] != 0) continue;
+                spf[i] = i;
+                for (size_t j = 2; i*j < max; j++)
+                        if (spf[i*j] == 0)
+                                spf[i*j] = i;
+        }
+
+        size_t n, x;
+        std::cin >> n;
+        for (size_t i = 0; i < n; i++) {
+                std::cin >> x;
+                std::cout << ndiv(x) << "\n";
+        }
+}