max_slice_sum() {
    local -n _arr="$1"
    local _tmp=-9223372036854775808 _max=-9223372036854775808
    local _v
    for _v in "${_arr[@]}"; do
        if (( _tmp + _v > _v )); then _tmp=$(( _tmp + _v )); else _tmp=$_v; fi
        if (( _tmp > _max )); then _max=$_tmp; fi
    done
    echo "$_max"
}