Solve 'Integers: Recreation One' kata

include/integers_recreation_one/SumSquaredDivisors.h

@@ -0,0 +1,12 @@
+#ifndef CPP_KATAS_SUMSQUAREDDIVISORS_H
+#define CPP_KATAS_SUMSQUAREDDIVISORS_H
+
+#include <utility>
+#include <vector>
+
+class SumSquaredDivisors {
+public:
+    static std::vector<std::pair<long long, long long>> listSquared(long long m, long long n);
+};
+
+#endif //CPP_KATAS_SUMSQUAREDDIVISORS_H

src/integers_recreation_one/SumSquaredDivisors.cpp

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+#include <utility>
+#include <vector>
+#include <cmath>
+
+/**
+ * https://www.codewars.com/kata/55aa075506463dac6600010d/train/cpp
+ */
+class SumSquaredDivisors {
+public:
+    static std::vector<std::pair<long long, long long>> listSquared(long long m, long long n);
+};
+
+static std::vector<long long> divisors(long long n) {
+    std::vector<long long> divs;
+
+    for (long long i = 1; i * i <= n; i++) {
+        if (n % i == 0) {
+            divs.push_back(i);
+
+            if (i != n / i) {
+                divs.push_back(n / i);
+            }
+        }
+    }
+
+    return divs;
+}
+
+static long long squaredSum(const std::vector<long long> &divs) {
+    long long sum = 0;
+
+    for (long long div: divs) {
+        sum += div * div;
+    }
+
+    return sum;
+}
+
+static bool isSquare(long long n) {
+    auto root = (long long) sqrt(n);
+    return root * root == n;
+}
+
+std::vector<std::pair<long long, long long>> SumSquaredDivisors::listSquared(long long int m, long long int n) {
+    std::vector<std::pair<long long, long long>> result;
+
+    for (long long i = m; i <= n; i++) {
+        std::vector<long long> divs = divisors(i);
+        long long sum = squaredSum(divs);
+
+        if (isSquare(sum)) {
+            result.emplace_back(i, sum);
+        }
+    }
+
+    return result;
+}

test/integers_recreation_one/SumSquaredDivisors_test.cpp

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+#include <utility>
+#include <vector>
+#include <igloo/igloo_alt.h>
+#include "integers_recreation_one/SumSquaredDivisors.h"
+
+using namespace igloo;
+
+using Result = std::vector<std::pair<long long, long long>>;
+
+void testequal(const Result &ans, const Result &sol) {
+    Assert::That(ans, Equals(sol));
+}
+
+void dotest(long long m, long long n, const Result &expected) {
+    testequal(SumSquaredDivisors::listSquared(m, n), expected);
+}
+
+Describe(listSquared_Tests) {
+    It(Fixed_Tests) {
+        dotest(1, 250, {{1,   1},
+                        {42,  2500},
+                        {246, 84100}});
+        dotest(42, 250, {{42,  2500},
+                         {246, 84100}});
+        dotest(250, 500, {{287, 84100}});
+        dotest(300, 600, {});
+    }
+};