diff options
| -rw-r--r-- | lib/stdlib/src/queue.erl | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/lib/stdlib/src/queue.erl b/lib/stdlib/src/queue.erl index afe917b151..bc1bd06534 100644 --- a/lib/stdlib/src/queue.erl +++ b/lib/stdlib/src/queue.erl @@ -472,22 +472,24 @@ init(Q) -> drop_r(Q). -compile({inline, [{r2f,1},{f2r,1}]}). -%% Move all but two from R to F, if there are at least three +%% Move half of elements from R to F, if there are at least three r2f([]) -> {[],[]}; r2f([_]=R) -> {[],R}; r2f([X,Y]) -> {[X],[Y]}; -r2f([X,Y|R]) -> - {[X,Y],lists:reverse(R, [])}. +r2f(List) -> + {FF,RR} = lists:split(length(List) div 2 + 1, List), + {FF,lists:reverse(RR, [])}. -%% Move all but two from F to R, if there are enough +%% Move half of elements from F to R, if there are enough f2r([]) -> {[],[]}; f2r([_]=F) -> {F,[]}; f2r([X,Y]) -> {[Y],[X]}; -f2r([X,Y|F]) -> - {lists:reverse(F, []),[X,Y]}. +f2r(List) -> + {FF,RR} = lists:split(length(List) div 2 + 1, List), + {lists:reverse(RR, []),FF}. |