三元组的补充（稀疏矩阵的乘法）

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <vector>
  5 
  6 using namespace std;
  7 
  8 class Node {
  9 public:
 10     int row,col;
 11     int value;
 12     Node (int r,int c,int v) {
 13         row = r;
 14         col = c;
 15         value = v;
 16     }
 17 };
 18 
 19 class Matrix {
 20 private:
 21     int rownum,colnum;
 22     int ElementNumber;
 23     vector<int>rowstart;
 24     vector<int>colstart;
 25     vector<Node> data;
 26 
 27 public:
 28     Matrix() {
 29         ElementNumber = 0;
 30         rowstart.clear();
 31         colstart.clear();
 32         data.clear();
 33     }
 34     ~Matrix() {
 35         ElementNumber = 0;
 36         rowstart.clear();
 37         colstart.clear();
 38         data.clear();
 39     }
 40 
 41     void Start() {
 42         rowstart.resize(1000);
 43         colstart.resize(1000);
 44         int rownumber[1000];
 45         memset(rownumber,0,sizeof(rownumber));
 46         for (int i = 0;i < ElementNumber;i++) rownumber[data[i].row]++;
 47         for (int i = 1;i < rownum;i++) rowstart[i] = rowstart[i - 1] + rownumber[i - 1];
 48 
 49         int colnumber[1000];
 50         memset(colnumber,0,sizeof(colnumber));
 51         for (int i = 0;i < ElementNumber;i++) colnumber[data[i].col]++;
 52         for (int i = 1;i < colnum;i++) {
 53             colstart[i] = colstart[i - 1] + colnumber[i - 1];
 54         }
 55     }
 56 
 57     void input() {
 58         cin >> rownum >> colnum;
 59         for (int i = 0;i < rownum;i++) {
 60             int value;
 61             for (int j = 0;j < colnum;j++) {
 62                 cin >> value;
 63                 if (value) {
 64                     data.push_back(Node(i,j,value));
 65                     ElementNumber++;
 66                 }
 67             }
 68         }
 69         Start();
 70     }
 71 
 72     void output() {
 73         int pos = 0;
 74         for (int i = 0;i < rownum;i++) {
 75             for (int j = 0;j < colnum;j++) {
 76                 if (pos < ElementNumber && data[pos].row == i && data[pos].col == j) {
 77                     cout << data[pos++].value << " ";
 78                 }
 79                 else cout << 0 << " ";
 80             }
 81             cout << endl;
 82         }
 83     }
 84 
 85     void Trans_1() {
 86         vector <Node> temp(data.begin(), data.end());
 87         int num = 0;
 88         for (int i = 0;i < colnum;i++) {
 89             for (int j = 0;j < ElementNumber;j++) {
 90                 if (temp[j].col == i) {
 91                     data[num].row = temp[j].col;
 92                     data[num].col = temp[j].row;
 93                     data[num].value = temp[j].value;
 94                     num++;
 95                 }
 96             }
 97         }
 98         swap(rownum,colnum);
 99         swap(colstart,rowstart);
100     }
101 
102     void Trans_2() {
103         vector <Node> temp(data.begin(), data.end());
104         vector <int> start(colstart.begin(),colstart.end());
105         for (int i = 0;i < ElementNumber;i++) {
106             int j = start[temp[i].col] ++;
107             data[j].row = temp[i].col;
108             data[j].col = temp[i].row;
109             data[j].value = temp[i].value;
110         }
111         swap(colnum,rownum);
112         swap(colstart,rowstart);
113     }
114 
115     Matrix Multi(Matrix MX) {
116         Matrix C;
117         if (ElementNumber * MX.ElementNumber != 0) {
118             for (int i = 0;i < rownum;i++) {
119                 int ctemp[colnum + 1];
120                 memset(ctemp,0,sizeof(ctemp));
121                 int tp;
122                 if (i == rownum - 1) {
123                     tp = ElementNumber;
124                 }
125                 else {
126                     tp = rowstart[i + 1];
127                 }
128 
129                 for (int j = rowstart[i];j < tp;j++) {
130                     int k = data[j].col;
131                     int t;
132                     if (k == MX.rownum - 1) {
133                         t = MX.ElementNumber;
134                     }
135                     else {
136                         t = MX.rowstart[k + 1];
137                     }
138                     for (int l = MX.rowstart[k];l < t;l++) {
139                         ctemp[MX.data[l].col] += data[j].value * MX.data[l].value;
140                     }
141                 }
142                 for (int l = 0;l < MX.colnum;l++) {
143                     if (ctemp[l]) {
144                         C.data.push_back(Node(i,l,ctemp[l]));
145                         C.ElementNumber++;
146                     }
147                 }
148             }
149         }
150         C.rownum = rownum;
151         C.colnum = MX.colnum;
152         C.Start();
153         return C;
154     }
155 };
156 
157 int main () {
158     Matrix A;
159     A.input();
160     Matrix B;
161     B.input();
162     Matrix C = A.Multi(B);
163     C.output(); 
164 }