From 07567e4c8a7cad19815c93eeb046530eb613a8a3 Mon Sep 17 00:00:00 2001
From: Eric Mertens <emertens@gmail.com>
Date: Sun, 27 Nov 2022 11:01:31 -0800
Subject: [PATCH] queue

---
 2018/15.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/2018/15.cpp b/2018/15.cpp
index 601d79c..a11358e 100644
--- a/2018/15.cpp
+++ b/2018/15.cpp
@@ -8,7 +8,7 @@
 #include <sstream>
 #include <string>
 #include <tuple>
-#include <vector>
+#include <queue>
 
 #include <doctest.h>
 
@@ -114,18 +114,18 @@ auto Game::Move(Coord my_coord, char my_team) -> std::optional<Coord>
   Coord best_end;    // initialized when best_start is non-empty
   int best_distance; // initialized when best_start is non-empty
 
-  std::deque<std::tuple<Coord, Coord, int>> todo;
+  std::queue<std::tuple<Coord, Coord, int>> todo;
   for (auto const dir : reading_order) {
     auto const start = my_coord + dir;
     if (grid_[start] == '.') {
-      todo.push_back({start, start, 1});
+      todo.push({start, start, 1});
     }
   }
 
   std::set<Coord> seen;
   while (!todo.empty()) {
     auto const [start, cursor, steps] = todo.front();
-    todo.pop_front();
+    todo.pop();
 
     if (best_start) {
       if (best_distance < steps) break;
@@ -135,7 +135,7 @@ auto Game::Move(Coord my_coord, char my_team) -> std::optional<Coord>
       for (auto const dir : reading_order) {
         auto const next = cursor + dir;
         if (grid_[next] == '.') {
-          todo.push_back({start, cursor + dir, steps+1});
+          todo.push({start, cursor + dir, steps+1});
         }
       }
     }