do day 6

input/2025-6.sample.txt

@@ -0,0 +1,4 @@
+123 328  51 64 
+ 45 64  387 23 
+  6 98  215 314
+*   +   *   +  

src/day6.cpp

@@ -0,0 +1,102 @@
+// :autocmd BufWritePost *.cpp :silent exec "!./build 6"
+#include <cstdint>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+using Grid = std::vector<std::string>;
+using Ops = std::vector<char>;
+
+int64_t part_1(const Grid &grid, const Ops &ops);
+int64_t part_2(const Grid &grid, const Ops &ops);
+
+int main() {
+  Grid grid;
+  std::string line;
+  std::ifstream file{"input/2025-6.txt"};
+  size_t row{0};
+  while (std::getline(file, line)) {
+    grid.emplace_back(line);
+    row += 1;
+  }
+  auto op_line{grid[grid.size() - 1]};
+  std::istringstream reader{op_line};
+  char op;
+  std::vector<char> ops;
+  while (reader >> op) {
+    ops.push_back(op);
+  }
+  std::cout << part_1(grid, ops) << std::endl;
+  std::cout << part_2(grid, ops) << std::endl;
+  return 0;
+}
+
+int64_t part_1(const Grid &grid, const Ops &ops) {
+  std::vector<std::vector<int64_t>> blocks;
+  for (auto i{0}; i < grid.size() - 1; ++i) {
+    std::vector<int64_t> current_line{};
+    auto line = grid[i];
+    std::istringstream reader{line};
+    int64_t num;
+    while (reader >> num) {
+      current_line.push_back(num);
+    }
+    blocks.emplace_back(current_line);
+  }
+  int64_t ans{0};
+  for (int64_t i{0}; i < blocks[0].size(); ++i) {
+    if (ops[i] == '*') {
+      int64_t curr{1};
+      for (int64_t j{0}; j < blocks.size(); ++j) {
+        curr *= blocks[j][i];
+      }
+      ans += curr;
+    } else {
+      int64_t curr{0};
+      for (int64_t j{0}; j < blocks.size(); ++j) {
+        curr += blocks[j][i];
+      }
+      ans += curr;
+    }
+  }
+  return ans;
+}
+
+int64_t part_2(const Grid &grid, const Ops &ops) {
+  size_t op_iter{};
+  uint64_t ans{};
+  std::vector<int64_t> block;
+  for (size_t col{}; col < grid[0].length(); ++col) {
+    std::string col_str{""};
+    for (size_t row{}; row < grid.size() - 1; ++row) {
+      char c{grid[row][col]};
+      if (c >= '0' && c <= '9') {
+        col_str += c;
+      }
+    }
+    if (col_str == "") {
+      if (ops[op_iter] == '*') {
+        int64_t temp{1};
+        for (auto n : block) {
+          temp *= n;
+        }
+        ans += temp;
+      } else {
+        auto temp{0};
+        for (auto n : block) {
+          temp += n;
+        }
+        ans += temp;
+      }
+      block.clear();
+      ++op_iter;
+      continue;
+    } else {
+      int64_t num{std::stoll(col_str)};
+      block.push_back(num);
+    }
+  }
+  return ans;
+}