From 2db5c84bf8d08a6a5e832cba5c9b44081a4d1996 Mon Sep 17 00:00:00 2001
From: Eric Mertens <emertens@galois.com>
Date: Tue, 28 Mar 2023 16:49:04 -0700
Subject: [PATCH] 13: fancier boost index()

---
 2022/13.cpp | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/2022/13.cpp b/2022/13.cpp
index cde1d71..5f4499e 100644
--- a/2022/13.cpp
+++ b/2022/13.cpp
@@ -1,21 +1,19 @@
 #include <array>
 #include <cstdint>
 #include <iostream>
-#include <set>
 #include <sstream>
-#include <tuple>
-#include <vector>
 #include <variant>
+#include <vector>
+
+#include <boost/spirit/include/qi.hpp>
+#include <boost/phoenix.hpp>
+#include <boost/range/adaptor/indexed.hpp>
 
 #include <doctest.h>
 
 #include <aocpp/Startup.hpp>
 #include <aocpp/Overloaded.hpp>
 
-#include <boost/spirit/include/qi.hpp>
-#include <boost/phoenix.hpp>
-#include <boost/range/irange.hpp>
-
 namespace {
 
 namespace phx = boost::phoenix;
@@ -29,7 +27,6 @@ struct Tree {
   std::variant<std::int64_t, Trees> rep;
 };
 
-
 auto operator<(Tree const& x, std::int64_t y) -> bool;
 auto operator<(std::int64_t x, Tree const& y) -> bool;
 
@@ -98,8 +95,8 @@ auto Parse(std::istream & in) -> Input
 auto Part1(Input const& input) -> std::size_t
 {
   std::int64_t result {0};
-  for (auto const i : boost::irange(input.size())) {
-    if (input[i][0] < input[i][1]) {
+  for (auto const& [i,pair] : boost::adaptors::index(input)) {
+    if (pair[0] < pair[1]) {
       result += i + 1;
     }
   }