java - How to implement 2D list? -


i have matrix having r rows , c columns. have store matrix in 2-d array. see figure below.

enter image description here

i find minimum number in each row. if minimum number lies in first column add minimum listc1.

consider above figure.

in first row r1 minimum number 2 , lies in column c1 want add 2 in listc1. in second row r2 minimum number 4 , lies in column c3 want add 4 in listc3. in third row r3 minimum number 5 , lies in column c2 want add 5 in listc2. in nutshell if minimum number lies in first column add minimum number in first list listc1, if minimum number lies in second column add minimum number in second list listc2, if minimum number lies in third column add minimum number in third list listc3 , on , forth.

now issue facing how create list of list implement above logic. have developed code (see below) not working properly. please me in regard 

note:  ther number of columns may vary 3 30    final float[][] matrix = {             {2f, 8f, 5f},             {9f, 7f, 4f},             {8f, 5f, 6f},             {7f, 3f, 9f},             {1f, 5f, 5f},             {8f, 7f, 5f},         };          map<integer, arraylist<float>> minsmap = new linkedhashmap<>();            for(int row=0; row < matrix.length; row++)         {             float min = float.max_value;             int mc = 0;              for(int col=0; col < matrix[row].length; col++)             {                 if(matrix[row][col] < min)                  {                     min = matrix[row][col];                     mc = col;                 }                  arraylist<float> minlist = minsmap.get(mc);                  if(minlist == null)                  {                     minlist = new arraylist<>();                     minsmap.put(mc, minlist);                 }                 minlist.add(min);             }          }          for(java.util.map.entry<integer, arraylist<float>> e : minsmap.entryset())          {             system.out.println("min values in column " + e.getkey() + ": " + e.getvalue());         }

nestedgroup initialized once used columns. not correct, need nested group each column.

take @ code, uses map holding lists of minimum values.

private final static float[][] matrix = {     {2f, 8f, 5f},     {9f, 7f, 4f},     {8f, 5f, 6f},     {7f, 3f, 9f},     {1f, 5f, 5f},     {8f, 7f, 5f}, };   @test public void minofmatrixcolumn() {     map<integer, list<float>> minsmap = new linkedhashmap<>();     for(int r = 0; r < matrix.length; r++) {         float min = float.max_value;         int mc = 0;         for(int c = 0; c < matrix[r].length; c++) {             if(matrix[r][c] < min) {                 min = matrix[r][c];                 mc = c;             }         }         list<float> minlist = minsmap.get(mc);         if(minlist == null) {             minlist = new arraylist<>();             minsmap.put(mc, minlist);         }         minlist.add(min);     }     for(entry<integer, list<float>> e : minsmap.entryset()) {         system.out.println("min values in column " + e.getkey() + ": " + e.getvalue());     } }

output

min values in column 0: [2.0, 1.0] min values in column 2: [4.0, 5.0] min values in column 1: [5.0, 3.0]

note lists not ordered column index.


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