From 8319d391be8fe6bf82043132196057104410891e Mon Sep 17 00:00:00 2001
From: studiosi <david@studiosi.es>
Date: Mon, 17 Aug 2026 21:14:50 +0300
Subject: [PATCH] Solved: 31 - Transform and Reduce

---
 .../08_stl_algorithms/src/transform_reduce.cpp  | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/modules/08_stl_algorithms/src/transform_reduce.cpp b/modules/08_stl_algorithms/src/transform_reduce.cpp
index 0e17e8b..b2d87eb 100644
--- a/modules/08_stl_algorithms/src/transform_reduce.cpp
+++ b/modules/08_stl_algorithms/src/transform_reduce.cpp
@@ -1,9 +1,20 @@
 #include "transform_reduce.hpp"
 
+#include <algorithm>
+
 namespace stl_algorithms {
 
-auto square_all(const std::vector<int>& data) -> std::vector<int> { (void)data; return {}; }
-auto sum_all(const std::vector<int>& data) -> int { (void)data; return 0; }
-auto product_positive(const std::vector<int>& data) -> long long { (void)data; return 0; }
+auto square_all(const std::vector<int>& data) -> std::vector<int> {
+    auto result = std::vector<int>{};
+    result.reserve(data.size());
+    std::ranges::transform(data, std::back_inserter(result), [](const int value) { return value * value; });
+    return result;
+}
+auto sum_all(const std::vector<int>& data) -> int {
+    return std::ranges::fold_left(data, 0, std::plus<int>{});
+}
+auto product_positive(const std::vector<int>& data) -> long long {
+    return std::ranges::fold_left(data, 1, [](const int accumulator, const int value) { return value > 0 ? value * accumulator : accumulator; });
+}
 
 }  // namespace stl_algorithms