konhon

忘掉過去，展望未來。找回自我，超越自我。
逃避不一定躲的過, 面對不一定最難過, 孤單不一定不快樂, 得到不一定能長久, 失去不一定不再擁有, 可能因為某個理由而傷心難過, 但我卻能找個理由讓自己快樂.

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[轉(zhuǎn)]樹形算法

我喜歡解決算法問題哈哈
為了解決這個問題我寫了一個樹狀數(shù)據(jù)結(jié)構(gòu)
根節(jié)點(diǎn)為世界(我想這個根夠大了吧)
下面有兩個子節(jié)點(diǎn) 分別為亞洲歐洲
亞洲的下面還有幾個節(jié)點(diǎn)分別是中國韓國......
中國下面的幾個節(jié)點(diǎn)分別是福建省湖北省......
以次類推
就是一個樹啦 (不知道這個樹是不是樓主需要的反正沒事寫著玩唄起碼能對樓主有所啟發(fā)吧)
下面是代碼

首先是 Type (一個對象是一條記錄)

package?beans;

public?class?Type?{

????????private?int?id;

????????private?String?name;

????????private?int?parentid;

????????public?int?getId()?{

????????????????return?id;

????????}

????????public?void?setId(int?id)?{

????????????????this.id?=?id;

????????}

????????public?String?getName()?{

????????????????return?name;

????????}

????????public?void?setName(String?name)?{

????????????????this.name?=?name;

????????}

????????public?int?getParentid()?{

????????????????return?parentid;

????????}

????????public?void?setParentid(int?parentid)?{

????????????????this.parentid?=?parentid;

????????}

}

然后是 TypeTree 繼承與Type 比Type 多一個ArrayList屬性是 childtype 里面的每一個元素應(yīng)該是其子節(jié)點(diǎn)TypeTree
(arrayList 里面可能有多個元素,每個元素都是個TypeTree??也可能沒有)

package?beans;

import?java.util.ArrayList;

public?class?TypeTree?extends?Type?{

????????private?ArrayList?childtype;

????????public?ArrayList?getChildtype()?{

????????????????return?childtype;

????????}

????????public?void?setChildtype(ArrayList?childtype)?{

????????????????this.childtype?=?childtype;

????????}

}

然后是最重要的生成TypeTree 的類??這個類可以把 Type[] 轉(zhuǎn)換成一個 TypeTree 對象
這個TypeTree 對象是模擬樹狀結(jié)構(gòu)的??每一個節(jié)點(diǎn)都是一個Type
樹的結(jié)構(gòu)也都是按照數(shù)據(jù)庫表中??id??與parentid 結(jié)構(gòu)的

package?beans;

import?java.util.ArrayList;

public?class?Tree?{

????????private?Type[]?type;

????????private?TypeTree?typeTree;

????????public?ArrayList?getTree(int?parentid)?{

????????????????ArrayList?arrayList?=?new?ArrayList();

????????????????for?(int?i?=?0;?i?<?type.length;?i++)?{

????????????????????????if?(type[i].getParentid()?==?parentid)?{

????????????????????????????????TypeTree?t?=?new?TypeTree();

????????????????????????????????t.setId(type[i].getId());

????????????????????????????????t.setName(type[i].getName());

????????????????????????????????t.setParentid(type[i].getParentid());

????????????????????????????????t.setChildtype(getTree(type[i].getId()));

????????????????????????????????arrayList.add(t);

????????????????????????????????System.out.println("Tree"?+?t.getId()?+?"?"?+?t.getName()?+?"?"

????????????????????????????????????????????????+?t.getParentid());

????????????????????????}

????????????????}

????????????????return?arrayList;

????????}

????????public?TypeTree?createTree()?{

????????????????this.typeTree?=?new?TypeTree();

????????????????this.typeTree.setId(0);

????????????????this.typeTree.setName("world");

????????????????this.typeTree.setParentid(-1);

????????????????this.typeTree.setChildtype(this.getTree(0));

????????????????return?this.typeTree;

????????}

????????public?Type[]?getType()?{

????????????????return?type;

????????}

????????public?void?setType(Type[]?type)?{

????????????????this.type?=?type;

????????}

}

最后是我測試用的類連接數(shù)據(jù)庫寫的很簡單別見笑啊
這個類可以直接運(yùn)行只要你建立了數(shù)據(jù)源呵呵
其中把樹中所有元素顯示出來也是用了一個遞歸的方法( public static void display(TypeTree typeTree) )
這個遞歸的方法在你的JSP顯示的時候可能有用

package?beans;

import?java.sql.*;

import?java.util.ArrayList;

public?class?TreeTest?{

????????Connection?con?=?null;

????????Statement?sta?=?null;

????????ResultSet?res?=?null;

????????String?sql?=?"select?*?from?treetable";

????????public?Type[]?qiaolian()?{

????????????????ArrayList?arrayList?=?new?ArrayList();

????????????????try?{

????????????????????????Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

????????????????}?catch?(ClassNotFoundException?e)?{

????????????????????????System.out.println(e);

????????????????}

????????????????try?{

????????????????????????con?=?DriverManager.getConnection("jdbc:odbc:hib",?"sa",?"");

????????????????}?catch?(SQLException?e)?{

????????????????????????System.out.println(e);

????????????????}

????????????????try?{

????????????????????????sta?=?con.createStatement();

????????????????????????res?=?sta.executeQuery(sql);

????????????????????????while?(res.next())?{

????????????????????????????????Type?t?=?new?Type();

????????????????????????????????t.setId(res.getInt("id"));

????????????????????????????????t.setName(res.getString("name"));

????????????????????????????????t.setParentid(res.getInt("parentid"));

????????????????????????????????arrayList.add(t);

????????????????????????}

????????????????}?catch?(SQLException?e)?{

????????????????????????System.out.println(e);

????????????????}

????????????????Type[]?type?=?new?Type[arrayList.size()];

????????????????for?(int?i?=?0;?i?<?arrayList.size();?i++)?{

????????????????????????type[i]?=?(Type)?arrayList.get(i);

????????????????}

????????????????return?type;

????????}

????????public?static?void?main(String[]?args)?{

????????????????TreeTest?treeTest?=?new?TreeTest();

????????????????Type[]?ty?=?treeTest.qiaolian();

????????????????Tree?tree?=?new?Tree();

????????????????tree.setType(ty);

????????????????TypeTree?typeTree?=?tree.createTree();

????????????????display(typeTree);

????????}

????????public?static?void?display(TypeTree?typeTree)?{

????????????????TypeTree?now?=?typeTree;

????????????????System.out.println(now.getId()?+?"\t"?+?now.getName()?+?"\t"

????????????????????????????????+?now.getParentid()?+?"\t"?+?"child?num"

????????????????????????????????+?now.getChildtype().size());

????????????????if?(now.getChildtype()?!=?null)?{

????????????????????????ArrayList?arrayList?=?now.getChildtype();

????????????????????????for?(int?i?=?0;?i?<?arrayList.size();?i++)?{

????????????????????????????????display((TypeTree)?arrayList.get(i));

????????????????????????}

????????????????}

????????}

}

posted on 2006-03-31 02:54 konhon 優(yōu)華閱讀(479) 評論(0) 編輯收藏所屬分類: JSP/Servlet

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