{"id":21,"date":"2025-11-09T20:37:30","date_gmt":"2025-11-09T12:37:30","guid":{"rendered":"https:\/\/tblog.zeabur.app\/?p=21"},"modified":"2025-11-09T20:38:22","modified_gmt":"2025-11-09T12:38:22","slug":"%e9%a2%98%e8%a7%a3%ef%bc%9auva11234-expressions","status":"publish","type":"post","link":"https:\/\/tblog.zeabur.app\/?p=21","title":{"rendered":"\u9898\u89e3 UVA11234 Expressions"},"content":{"rendered":"\n

\u95ee\u9898\u63cf\u8ff0<\/h2>\n\n\n\n

\u5c06\u4e00\u4e2a\u540e\u7f00\u8868\u8fbe\u5f0f\uff08\u9006\u6ce2\u5170\u8868\u793a\u6cd5\uff09\u8f6c\u6362\u6210\u53e6\u4e00\u79cd\u5f62\u5f0f\uff0c\u4f7f\u5f97\u4f7f\u7528\u961f\u5217\u8fdb\u884c\u8ba1\u7b97\u7684\u7ed3\u679c\u4e0e\u4f7f\u7528\u6808\u8ba1\u7b97\u539f\u8868\u8fbe\u5f0f\u7684\u7ed3\u679c\u76f8\u540c\u3002<\/p>\n\n\n\n

\u601d\u8def<\/h2>\n\n\n\n
    \n
  1. \u6784\u5efa\u8868\u8fbe\u5f0f\u6811\uff1a\u4ece\u5de6\u5230\u53f3\u8bfb\u53d6\u8f93\u5165\u7684\u540e\u7f00\u8868\u8fbe\u5f0f\uff0c\u6784\u5efa\u4e00\u4e2a\u4e8c\u53c9\u8868\u8fbe\u5f0f\u6811\u3002<\/li>\n\n\n\n
  2. bfs \u904d\u5386\uff1a\u5bf9\u6784\u5efa\u597d\u7684\u8868\u8fbe\u5f0f\u6811\u8fdb\u884c\u5e7f\u5ea6\u4f18\u5148\u641c\u7d22\u3002<\/li>\n\n\n\n
  3. \u53cd\u8f6c\u7ed3\u679c\uff1a\u5c06\u904d\u5386\u7684\u7ed3\u679c\u53cd\u8f6c\uff0c\u5c31\u5f97\u5230\u4e86\u6700\u7ec8\u7b54\u6848\u3002<\/li>\n<\/ol>\n\n\n\n

    BFS \u53cd\u8f6c\u5206\u6790<\/h2>\n\n\n\n

    1. \u521d\u59cb\u72b6\u6001<\/h3>\n\n\n\n
    \"\"\/<\/div><\/figure>\n\n\n\n

    \u8868\u8fbe\u5f0f\u6811\u6839\u8282\u70b9\u4e3a A\uff0c\u5176\u4ed6\u8282\u70b9\u6309\u5c42\u6b21\u6392\u5217\u3002<\/p>\n\n\n\n

    2. BFS \u7b2c\u4e00\u5c42<\/h3>\n\n\n\n
    \"\"\/<\/div><\/figure>\n\n\n\n

    \u7b2c\u4e00\u6b65\uff0c\u8bbf\u95ee\u6839\u8282\u70b9 A\u3002\u5c06 A \u7684\u503c\u6dfb\u52a0\u5230\u7ed3\u679c\u5b57\u7b26\u4e32\u4e2d\uff0c\u5e76\u5c06 A \u7684\u5b50\u8282\u70b9 B \u548c C \u52a0\u5165\u961f\u5217\u3002<\/p>\n\n\n\n

    3. BFS \u7b2c\u4e8c\u5c42<\/h3>\n\n\n\n
    \"\"\/<\/div><\/figure>\n\n\n\n

    \u63a5\u4e0b\u6765\u8bbf\u95ee A \u7684\u5b50\u8282\u70b9 B \u548c C\u3002\u5c06 B \u548c C \u7684\u503c\u6dfb\u52a0\u5230\u7ed3\u679c\u5b57\u7b26\u4e32\u4e2d\uff0c\u5e76\u5c06\u5b83\u4eec\u7684\u5b50\u8282 D\u3001E\u3001F \u548c G \u52a0\u5165\u961f\u5217\u3002<\/p>\n\n\n\n

    4. BFS \u7b2c\u4e09\u5c42<\/h3>\n\n\n\n
    \"\"\/<\/div><\/figure>\n\n\n\n

    \u6700\u540e\u8bbf\u95ee B \u548c C \u7684\u5b50\u8282\u70b9 D\u3001E\u3001F \u548c G\u3002\u5c06\u5b83\u4eec\u7684\u503c\u6dfb\u52a0\u5230\u7ed3\u679c\u5b57\u7b26\u4e32\u4e2d\u3002\u7531\u4e8e\u8fd9\u4e9b\u8282\u70b9\u6ca1\u6709\u5b50\u8282\u70b9\uff0c\u8df3\u51fa\u9012\u5f52\u3002<\/p>\n\n\n\n

    5. \u6700\u7ec8\u7ed3\u679c<\/h3>\n\n\n\n

    BFS \u904d\u5386\u7684\u7ed3\u679c\u5b57\u7b26\u4e32\u4e3a\uff1aABCDEFG\u3002<\/p>\n\n\n\n

    \u5c06\u8fd9\u4e2a\u7ed3\u679c\u53cd\u8f6c\u540e\uff0c\u5f97\u5230\u6700\u7ec8\u7b54\u6848\uff1aGFEDCBA\u3002<\/p>\n\n\n\n

    \u8fd9\u4e2a\u53cd\u8f6c\u540e\u7684\u5b57\u7b26\u4e32\u5c31\u662f\u6211\u4eec\u9700\u8981\u6c42\u7684\uff0c\u4f7f\u7528\u961f\u5217\u8ba1\u7b97\u65f6\u4e0e\u539f\u540e\u7f00\u8868\u8fbe\u5f0f\u4f7f\u7528\u6808\u8ba1\u7b97\u7ed3\u679c\u76f8\u540c\u7684\u65b0\u8868\u8fbe\u5f0f\u3002<\/p>\n\n\n\n

    \u4ee3\u7801\u5b9e\u73b0<\/h2>\n\n\n\n
    #include<bits\/stdc++.h>\n#include<ext\/pb_ds\/assoc_container.hpp>\n#include<ext\/pb_ds\/tree_policy.hpp>\n#define int long long\nusing namespace std;\nusing namespace __gnu_pbds;\nstruct Node \n{\n    char value;\n    Node *left,*right;\n    Node(char v):value(v),left(nullptr),right(nullptr){}\n};\nNode* build(const string& expr)\/\/\u5efa\u6811\n{\n    stack<Node*>st;\n    for (char c:expr) \n    {\n        Node* node=new Node(c);\n        if(isupper(c))\n        {\n            node->right=st.top();st.pop();\n            node->left=st.top();st.pop();\n        }\n        st.push(node);\n    }\n    return st.top();\n}\nstring bfs(Node* root)\/\/bfs \u904d\u5386\u641c\u7d22\n{\n    string ans;\n    queue<Node*>q;\n    q.push(root);\n    while(!q.empty()) \n    {\n        Node* node=q.front();q.pop();\n        ans+=node->value;\n        if(node->left) q.push(node->left);\n        if(node->right) q.push(node->right);\n    }\n    return ans;\n}\nsigned main() \n{\n    int T;\n    cin>>T;\n    while(T--)\n    {\n        string expr;\/\/\u8868\u8fbe\u5f0f\n        cin>>expr;\n        Node* root=build(expr);\n        string ans=bfs(root);\n        reverse(ans.begin(),ans.end());\/\/\u7ffb\u8f6c\n        cout<<ans<<endl;\n    }\n    return 0;\n}<\/code><\/pre>\n\n\n\n
    \u65f6\u95f4\u590d\u6742\u5ea6<\/h2>\n\n\n\n
    \u6784\u5efa\u8868\u8fbe\u5f0f\u6811\u548c\u5c42\u5e8f\u904d\u5386\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u90fd\u662f $O(n)$\uff0c\u5176\u4e2d $n$ \u662f\u8868\u8fbe\u5f0f\u7684\u957f\u5ea6\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
    \u95ee\u9898\u63cf\u8ff0 \u5c06\u4e00\u4e2a\u540e\u7f00\u8868\u8fbe\u5f0f\uff08\u9006\u6ce2\u5170\u8868\u793a\u6cd5\uff09\u8f6c\u6362\u6210\u53e6\u4e00\u79cd\u5f62\u5f0f\uff0c\u4f7f\u5f97\u4f7f\u7528\u961f\u5217\u8fdb\u884c\u8ba1\u7b97\u7684\u7ed3\u679c\u4e0e\u4f7f\u7528\u6808\u8ba1\u7b97\u539f\u8868\u8fbe\u5f0f\u7684\u7ed3 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[3],"class_list":["post-21","post","type-post","status-publish","format-standard","hentry","category-oi","tag-oi"],"featured_image_src":null,"author_info":{"display_name":"CaelumRadish_c","author_link":"https:\/\/tblog.zeabur.app\/?author=1"},"_links":{"self":[{"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=\/wp\/v2\/posts\/21","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=21"}],"version-history":[{"count":2,"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=\/wp\/v2\/posts\/21\/revisions"}],"predecessor-version":[{"id":23,"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=\/wp\/v2\/posts\/21\/revisions\/23"}],"wp:attachment":[{"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tblog.zeabur.app\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}