【单选题】
元素1，3，5，7按顺序依次入队列，按该队列的出队序列进栈，该栈的可能输出序列是（ ）（进栈出栈可以交替进行）。
①
A．7，5，1，3
②
B．7，3，1，5
③
C．5，1，3，7
④
D．7，5，3，1
【简答题】
<img src="https://huaweicloudobs.ahjxjy.cn/224B0D2CE45F5AC3E6C3C7EE3F7E30BA.png" title="5.png" alt="5.png"/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/4B930D57827F5A7F93C085282B5A04C2.png title=5.png alt=5.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/48D6719B7734A93DE6292129338A3CA5.png title=5-1.png alt=5-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/48AA6D7BB818C7DC17C07294D2419DB0.png title=5-2.png alt=5-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/6B7E4A2E27FEBFF63468755E016B2A66.png title=5-3.png alt=5-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/20C2EA782ED82AA925442EB081194764.png title=5-4.png alt=5-4.png/>
【单选题】
设 A = {1, 22, 43, 3}，B = {1, 32, 44, 2}，则差关系A-B的域fld(A-B)等于：
①
{1,3};
②
{1,2,4};
③
{1,2,3};
④
{2,3}.
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/27483DB2B2FC1AAF40C45FF5B4A0D349.png title=7.png alt=7.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/D594462BB5C4164FDFA0944CF623912C.png title=7-1.png alt=7-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/FA4E04E7F344C8C36FF15B9BBC2795DF.png title=7-2.png alt=7-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/ACF5C3328C49AA7DD6C0153DB71457B2.png title=7-3.png alt=7-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/1B1EC4FA0924D60EA21B1C16BB9C9BF1.png title=7-4.png alt=7-4.png/>
【单选题】
设 A = {1, 22, 43, 3}，B = {1, 32, 44, 2}，则并关系A∪B的定义域dom(A∪B)等于：
①
{1,2,3};
②
{1,2,3,4};
③
{2,3,4};
④
{3,4,2}.
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/762F04B897B10803258B783EB5CE8403.png title=7.png alt=7.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/105E33D043DE43212EE93C0F4F51024D.png title=7-1.png alt=7-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/329846DC72CE725CC2D0807F077CC479.png title=7-2.png alt=7-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/AAFE6581F59379576146F41CF442D822.png title=7-3.png alt=7-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/6826E117B65467CB2800E91808A07D25.png title=7-4.png alt=7-4.png/>
【单选题】
<imgsrc="http://121.251.253.213/doc/a@F4481B790DEA53F8BA784340D9E7DBD5.png/download?time=636002471591908737&token=C9861E965BE2A3F88E19FDB83A015858&filename=png"data-url="doc/a@F4481B790DEA53F8BA784340D9E7DBD5.png"data-preview_url_ueditor="doc/a@F4481B790DEA53F8BA784340D9E7DBD5.png"/>
①
<imgsrc="http://121.251.253.213/doc/a@49AD58B83D74079A52B9BC9D580A57F0.png/download?time=636002471674588883&token=5D0CC3E9D5071B5B99D33E11198168CF&filename=png"data-url="doc/a@49AD58B83D74079A52B9BC9D580A57F0.png"data-preview_url_ueditor="doc/a@49AD58B83D74079A52B9BC9D580A57F0.png"/>
②
<imgsrc="http://121.251.253.213/doc/a@7EFC8C78A5255FC23D2408BA7460C4B1.png/download?time=636002471771153052&token=C4DD6005C7D6AB83CC98365C90E96F7F&filename=png"data-url="doc/a@7EFC8C78A5255FC23D2408BA7460C4B1.png"data-preview_url_ueditor="doc/a@7EFC8C78A5255FC23D2408BA7460C4B1.png"/>
③
<imgsrc="http://121.251.253.213/doc/a@08C1F1E9561C37C7D96249E0FF936B6A.png/download?time=636002471855705201&token=48F4A7689592EAC7AC51D4A9DC7C61E9&filename=png"data-url="doc/a@08C1F1E9561C37C7D96249E0FF936B6A.png"data-preview_url_ueditor="doc/a@08C1F1E9561C37C7D96249E0FF936B6A.png"/>
④
<imgsrc="http://121.251.253.213/doc/a@33BDC224DA6CE3012ADE43A9FC77D6D6.png/download?time=636002471973797408&token=349E4644A1E20C4BDE3E18EC7BF17375&filename=png"data-url="doc/a@33BDC224DA6CE3012ADE43A9FC77D6D6.png"data-preview_url_ueditor="doc/a@33BDC224DA6CE3012ADE43A9FC77D6D6.png"/>