From 94da8ae68b1c14578b0fed9bca4581c5b5ad48aa Mon Sep 17 00:00:00 2001
From: Andrei Ovcharenko <a@krot.name>
Date: Fri, 31 Jul 2026 17:45:01 +0300
Subject: [PATCH] Fix deque index wraparound overflow

---
 src/main/java/algorithms/sprint2/Deque.java | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/main/java/algorithms/sprint2/Deque.java b/src/main/java/algorithms/sprint2/Deque.java
index c3f3141..408d102 100644
--- a/src/main/java/algorithms/sprint2/Deque.java
+++ b/src/main/java/algorithms/sprint2/Deque.java
@@ -68,11 +68,13 @@ static final class RingDeque {
         }
 
         private int next(int i) {
-            return (i+1) % cap;
+            i++;
+            return i == cap ? 0 : i;
         }
 
         private int prev(int i) {
-            return (i-1+cap) % cap;
+            i--;
+            return i == -1 ? cap - 1 : i;
         }
 
         boolean isEmpty() {