Do nothing for a segment of size 1.

1 files changed, 3 insertions, 0 deletions

diff --git a/quick-sort.cpp b/quick-sort.cpp
index 4e560a9..8e54ca7 100644
--- a/quick-sort.cpp
+++ b/quick-sort.cpp
@@ -10,6 +10,9 @@ typedef std::deque<int> list_t;
 
 size_t partition(list_t& lst, size_t left, size_t right, size_t pivot)
 {
+    if (left == right)
+        return left;
+
     list_t::value_type pivot_val = lst[pivot];
     swap(lst[pivot], lst[right]); // move pivot to end.
     size_t store_pos = left;