本文實例講述了Java數據結構之稀疏矩陣定義與用法。分享給大家供大家參考，具體如下：
稀疏矩陣非零元素的三元組類:
package com.clarck.datastructure.matrix;/** * 稀疏矩陣的壓縮存儲* * 稀疏矩陣非零元素的三元組類* * @author clarck * */public class Triple implements Comparable<Triple> { // 行號，列號， 元素值，默認訪問權限int row, colum, value; public Triple(int row, int colum, int value) { if (row < 0 || colum < 0) { throw new IllegalArgumentException("稀疏矩陣元素三元組的行/列序號非正數"); } this.row = row; this.colum = colum; this.value = value; } /** * 拷貝構造方法，複製一個三元組* * @param elem */ public Triple(Triple elem) { this(elem.row, elem.colum, elem.value); } @Override public String toString() { return "(" + row + ", " + colum + ", " + value + ")"; } /** * 兩個三元組是否相等，比較位置和元素值*/ public boolean equals(Object obj) { if (!(obj instanceof Triple)) return false; Triple elem = (Triple) obj; return this.row == elem.row && this.colum == elem.colum && this.value == elem.value; } /** * 根據三元組位置比較兩個三元組的大小，與元素值無關，約定三元組排序次序*/ @Override public int compareTo(Triple elem) { //當前三元組對像小if (this.row < elem.row || this.row == elem.row && this.colum < elem.colum) return -1; //相等，與equals方法含義不同if (this.row == elem.row && this.colum == elem.colum) return 0; //當前三元組對像大return 1; } /** * 加法， +=運算符作用* @param term */ public void add(Triple term) { if (this.compareTo(term) == 0) this.value += term.value; else throw new IllegalArgumentException("兩項的指數不同，不能相加"); } /** * 約定刪除元素* * @return */ public boolean removable() { //不存儲為0的元素return this.value == 0; } /** * 返回對稱位置矩陣元素的三元組* @return */ public Triple toSymmetry() { return new Triple(this.colum, this.row, this.value); } /** * 加法運算，重載運算符+ * @return */ public Triple plus(Triple term) { Triple tmp = new Triple(this); tmp.add(term); return tmp; }}三元組順序存儲的稀疏矩陣類:
package com.clarck.datastructure.matrix;import com.clarck.datastructure.linear.SeqList;/** * 稀疏矩陣的壓縮存儲* * 稀疏矩陣三元組順序表* * 三元組順序存儲的稀疏矩陣類* * @author clarck * */public class SeqSparseMatrix { // 矩陣行數、列數private int rows, columns; // 稀疏矩陣三元組順序表private SeqList<Triple> list; /** * 構造rows行，colums列零矩陣* * @param rows * @param columns */ public SeqSparseMatrix(int rows, int columns) { if (rows <= 0 || columns <= 0) throw new IllegalArgumentException("矩陣行數或列數為非正數"); this.rows = rows; this.columns = columns; // 構造空順序表，執行SeqList()構造方法this.list = new SeqList<Triple>(); } public SeqSparseMatrix(int rows, int columns, Triple[] elems) { this(rows, columns); // 按行主序插入一個元素的三元組for (int i = 0; i < elems.length; i++) this.set(elems[i]); } /** * 返回矩陣第i行第j列元素，排序順序表的順序查找算法，O(n) * * @param i * @param j * @return */ public int get(int i, int j) { if (i < 0 || i >= rows || j < 0 || j >= columns) throw new IndexOutOfBoundsException("矩陣元素的行或列序號越界"); Triple item = new Triple(i, j, 0); int k = 0; Triple elem = this.list.get(k); // 在排序順序表list中順序查找item對象while (k < this.list.length() && item.compareTo(elem) >= 0) { // 只比較三元組元素位置，即elem.row == i && elem.column == j if (item.compareTo(elem) == 0) return elem.value; // 查找到(i, j), 返回矩陣元素k++; elem = this.list.get(k); } return 0; } /** * 以三元組設置矩陣元素* * @param elem */ public void set(Triple elem) { this.set(elem.row, elem.colum, elem.value); } /** * 設置矩陣第row行第column列的元素值為value，按行主序在排序順序表list中更改或插入一個元素的三元組， O(n) * * @param row * @param column * @param value */ public void set(int row, int column, int value) { // 不存儲值為0元素if (value == 0) return; if (row >= this.rows || column >= this.columns) throw new IllegalArgumentException("三元組的行或列序號越界"); Triple elem = new Triple(row, column, value); int i = 0; // 在排序的三元組順序表中查找elem對象，或更改或插入while (i < this.list.length()) { Triple item = this.list.get(i); // 若elem存在，則更改改位置矩陣元素if (elem.compareTo(item) == 0) { // 設置順序表第i個元素為elem this.list.set(i, elem); return; } // elem 較大時向後走if (elem.compareTo(item) >= 0) i++; else break; } this.list.insert(i, elem); } @Override public String toString() { String str = "三元組順序表：" + this.list.toString() + "/n"; str += "稀疏矩陣" + this.getClass().getSimpleName() + "(" + rows + " * " + columns + "): /n"; int k = 0; // 返回第k個元素，若k指定序號無效則返回null Triple elem = this.list.get(k++); for (int i = 0; i < this.rows; i++) { for (int j = 0; j < this.columns; j++) if (elem != null && i == elem.row && j == elem.colum) { str += String.format("%4d", elem.value); elem = this.list.get(k++); } else { str += String.format("%4d", 0); } str += "/n"; } return str; } /** * 返回當前矩陣與smat相加的矩陣， smatc=this+smat,不改變當前矩陣，算法同兩個多項式相加* * @param smat * @return */ public SeqSparseMatrix plus(SeqSparseMatrix smat) { if (this.rows != smat.rows || this.columns != smat.columns) throw new IllegalArgumentException("兩個矩陣階數不同，不能相加"); // 構造rows*columns零矩陣SeqSparseMatrix smatc = new SeqSparseMatrix(this.rows, this.columns); int i = 0, j = 0; // 分別遍歷兩個矩陣的順序表while (i < this.list.length() && j < smat.list.length()) { Triple elema = this.list.get(i); Triple elemb = smat.list.get(j); // 若兩個三元組表示相同位置的矩陣元素，則對應元素值相加if (elema.compareTo(elemb) == 0) { // 相加結果不為零，則新建元素if (elema.value + elemb.value != 0) smatc.list.append(new Triple(elema.row, elema.colum, elema.value + elemb.value)); i++; j++; } else if (elema.compareTo(elemb) < 0) { // 將較小三元組複製添加到smatc順序表最後// 複製elema元素執行Triple拷貝構造方法smatc.list.append(new Triple(elema)); i++; } else { smatc.list.append(new Triple(elemb)); j++; } } // 將當前矩陣順序表的剩餘三元組複製添加到smatc順序表最後while (i < this.list.length()) smatc.list.append(new Triple(this.list.get(i++))); // 將smat中剩餘三元組複製添加到smatc順序表最後while (j < smatc.list.length()) { Triple elem = smat.list.get(j++); if (elem != null) { smatc.list.append(new Triple(elem)); } } return smatc; } /** * 當前矩陣與smat矩陣相加，this+=smat, 改變當前矩陣，算法同兩個多項式相加* * @param smat */ public void add(SeqSparseMatrix smat) { if (this.rows != smat.rows || this.columns != smat.columns) throw new IllegalArgumentException("兩個矩陣階數不同，不能相加"); int i = 0, j = 0; // 將mat的各三元組依次插入(或相加)到當前矩陣三元組順序表中while (i < this.list.length() && j < smat.list.length()) { Triple elema = this.list.get(i); Triple elemb = smat.list.get(j); // 若兩個三元組表示相同位置的矩陣元素，則對應元素值相加if (elema.compareTo(elemb) == 0) { // 相加結果不為0,則新建元素if (elema.value + elemb.value != 0) this.list.set(i++, new Triple(elema.row, elema.colum, elema.value + elemb.value)); else this.list.remove(i); j++; } else if (elema.compareTo(elemb) < 0) { // 繼續向後尋找elemb元素的插入元素i++; } else { // 複製elemb元素插入作為this.list的第i個元素this.list.insert(i++, new Triple(elemb)); j++; } } // 將mat中剩餘三元組依次復制插入當前矩陣三元組順序表中while (j < smat.list.length()) { this.list.append(new Triple(smat.list.get(j++))); } } // 深拷貝public SeqSparseMatrix(SeqSparseMatrix smat) { this(smat.rows, smat.columns); // 創建空順序表，默認容量this.list = new SeqList<Triple>(); // 複製smat中所有三元組對象for (int i = 0; i < smat.list.length(); i++) this.list.append(new Triple(smat.list.get(i))); } /** * 比較兩個矩陣是否相等*/ public boolean equals(Object obj) { if (this == obj) return true; if (!(obj instanceof SeqSparseMatrix)) return false; SeqSparseMatrix smat = (SeqSparseMatrix) obj; return this.rows == smat.rows && this.columns == smat.columns && this.list.equals(smat.list); } /** * 返迴轉置矩陣* @return */ public SeqSparseMatrix transpose() { //構造零矩陣，指定行數和列數SeqSparseMatrix trans = new SeqSparseMatrix(columns, rows); for (int i = 0; i < this.list.length(); i++) { //插入矩陣對稱位置元素的三元組trans.set(this.list.get(i).toSymmetry()); } return trans; }}測試類：
package com.clarck.datastructure.matrix;/** * 稀疏矩陣的壓縮存儲* * 稀疏矩陣三元組順序表* * 三元組順序表表示的稀疏矩陣及其加法運算* * @author clarck * */public class SeqSparseMatrix_test { public static void main(String args[]) { Triple[] elemsa = { new Triple(0, 2, 11), new Triple(0, 4, 17), new Triple(1, 1, 20), new Triple(3, 0, 19), new Triple(3, 5, 28), new Triple(4, 4, 50) }; SeqSparseMatrix smata = new SeqSparseMatrix(5, 6, elemsa); System.out.print("A " + smata.toString()); Triple[] elemsb = { new Triple(0, 2, -11), new Triple(0, 4, -17), new Triple(2, 3, 51), new Triple(3, 0, 10), new Triple(4, 5, 99), new Triple(1, 1, 0) }; SeqSparseMatrix smatb = new SeqSparseMatrix(5,6,elemsb); System.out.print("B " + smatb.toString()); SeqSparseMatrix smatc = smata.plus(smatb); System.out.print("C=A+B"+smatc.toString()); System.out.println(); smata.add(smatb); System.out.print("A+=B" + smata.toString()); System.out.println("C.equals(A)?" + smatc.equals(smata)); SeqSparseMatrix smatd = new SeqSparseMatrix(smatb); smatb.set(0,2,1); System.out.print("B " + smatb.toString()); System.out.print("D " + smatd.toString()); System.out.println("A轉置" + smata.transpose().toString()); }}運行結果：
A 三元組順序表：((0, 2, 11), (0, 4, 17), (1, 1, 20), (3, 0, 19), (3, 5, 28), (4, 4, 50))稀疏矩陣SeqSparseMatrix(5 * 6): 0 0 11 0 17 0 0 20 0 0 0 0 0 0 0 0 0 0 19 0 0 0 0 28 0 0 0 0 50 0B 三元組順序表：((0, 2, -11), (0, 4, -17), (2, 3, 51), (3, 0, 10), (4, 5, 99))稀疏矩陣SeqSparseMatrix(5 * 6): 0 0 -11 0 -17 0 0 0 0 0 0 0 0 0 0 51 0 0 10 0 0 0 0 0 0 0 0 0 0 99C=A+B三元組順序表：((1, 1, 20), (2, 3, 51), (3, 0, 29), (3, 5, 28), (4, 4, 50), (4, 5, 99))稀疏矩陣SeqSparseMatrix(5 * 6): 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 51 0 0 29 0 0 0 0 28 0 0 0 0 50 99A+=B三元組順序表：((1, 1, 20), (2, 3, 51), (3, 0, 29), (3, 5, 28), (4, 4, 50), (4, 5, 99))稀疏矩陣SeqSparseMatrix(5 * 6): 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 51 0 0 29 0 0 0 0 28 0 0 0 0 50 99C.equals(A)?trueB 三元組順序表：((0, 2, 1), (0, 4, -17), (2, 3, 51), (3, 0, 10), (4, 5, 99))稀疏矩陣SeqSparseMatrix(5 * 6): 0 0 1 0 -17 0 0 0 0 0 0 0 0 0 0 51 0 0 10 0 0 0 0 0 0 0 0 0 0 99D 三元組順序表：((0, 2, -11), (0, 4, -17), (2, 3, 51), (3, 0, 10), (4, 5, 99))稀疏矩陣SeqSparseMatrix(5 * 6): 0 0 -11 0 -17 0 0 0 0 0 0 0 0 0 0 51 0 0 10 0 0 0 0 0 0 0 0 0 0 99A轉置三元組順序表：((0, 3, 29), (1, 1, 20), (3, 2, 51), (4, 4, 50), (5, 3, 28), (5, 4, 99))稀疏矩陣SeqSparseMatrix(6 * 5): 0 0 0 29 0 0 20 0 0 0 0 0 0 0 0 0 0 51 0 0 0 0 0 0 50 0 0 0 28 99
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