fish() {
    local -n _a="$1"
    local -n _b="$2"
    local _size=${#_a[@]}
    local _dead=0
    local -a _stack=()
    local _i
    for ((_i = 0; _i < _size; _i++)); do
        if (( _b[_i] == 1 )); then
            _stack+=("${_a[_i]}")
        elif (( ${#_stack[@]} > 0 )); then
            while (( ${#_stack[@]} > 0 )); do
                ((_dead++))
                local _top=${_stack[-1]}
                if (( _a[_i] > _top )); then
                    unset '_stack[-1]'
                    _stack=("${_stack[@]}")
                else
                    break
                fi
            done
        fi
    done
    echo $(( _size - _dead ))
}