From 467674743fb638ea56713aecc719a80505b82a17 Mon Sep 17 00:00:00 2001
From: Lia Lenckowski <lialenck@protonmail.com>
Date: Wed, 27 Nov 2024 22:26:38 +0100
Subject: fix: 2-opt no longer crashes in debug builds due to an underflow

---
 src/tsp_approx.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/tsp_approx.rs b/src/tsp_approx.rs
index 2c6cbf9..e3448a1 100644
--- a/src/tsp_approx.rs
+++ b/src/tsp_approx.rs
@@ -292,7 +292,7 @@ fn refine_2_opt(dist_cache: &DistCache, tour: Vec<usize>) -> (bool, Vec<usize>)
     let mut tour: Vec<_> = tour
         .into_iter()
         .enumerate()
-        .map(|(i, v)| (i - 1, v, i + 1))
+        .map(|(i, v)| (i.wrapping_sub(1), v, i + 1))
         .collect();
     let n = tour.len();
     // fix boundary
-- 
cgit v1.2.3-70-g09d2