September 2017 Update

Task/Sudoku/Scilab/sudoku.scilab

@@ -0,0 +1,173 @@
+Init_board=[...
+5 3 0 0 7 0 0 0 0;...
+6 0 0 1 9 5 0 0 0;...
+0 9 8 0 0 0 0 6 0;...
+8 0 0 0 6 0 0 0 3;...
+4 0 0 8 0 3 0 0 1;...
+7 0 0 0 2 0 0 0 6;...
+0 6 0 0 0 0 2 8 0;...
+0 0 0 4 1 9 0 0 5;...
+0 0 0 0 8 0 0 7 9];
+
+break_point=1.0d5; //if 0 there will be no break
+
+function []=disp_board(board)
+    StringBoard=string(board);
+    for i=1:9
+        for j=1:9
+            if board(i,j)==0 then
+                StringBoard(i,j)='×';
+            end
+        end
+    end
+
+    StringBoard=[StringBoard, string(zeros(9,2))];
+    StringBoard=[StringBoard; string(zeros(2,11))];
+
+    for i=1:9
+        StringBoard(i,:)=[StringBoard(i,1:3), '|', StringBoard(i,4:6), '|', StringBoard(i,7:9)]
+    end
+    StringBoard(9:11,:)=StringBoard(7:9,:);
+    StringBoard(8,:)=strsplit('-----------');
+    StringBoard(5:7,:)=StringBoard(4:6,:);
+    StringBoard(4,:)=strsplit('-----------');
+
+    disp(StringBoard)
+endfunction
+
+function varargout=validate_input(input,position,board)
+    row=board(position(1),:);
+    column=board(:,position(2));
+    block=zeros(3,3);
+    if position(1)>=1 & position(1)<=3 then
+        i=0;
+    elseif position(1)>=4 & position(1)<=6 then
+        i=3;
+    else
+        i=6;
+    end
+    if position(2)>=1 & position(2)<=3 then
+        j=0;
+    elseif position(2)>=4 & position(2)<=6 then
+        j=3;
+    else
+        j=6;
+    end
+    block=board(i+1:i+3,j+1:j+3)
+
+    valid_input=%F;
+    valid_row=%F;
+    valid_col=%F;
+    valid_block=%F;
+
+    if find(input==row)==[] then
+        valid_row=%T;
+    end
+    if find(input==column)==[] then
+        valid_col=%T;
+    end
+    if find(input==block)==[] then
+        valid_block=%T;
+    end
+    if valid_row & valid_col & valid_block then
+        valid_input=%T;
+    end
+
+    varargout=list(valid_input,valid_row,valid_col,valid_block)
+endfunction
+
+function varargout=validate_board(board)
+    valid_flag1=%T;
+    for i=1:9
+        for j=1:9
+            if board(i,j)~= 0 then
+                check_board=Init_board;
+                check_board(i,j)=0;
+                valid_flag1=validate_input(board(i,j),[i j],check_board);
+                if ~valid_flag1 then
+                    break
+                end
+            end
+        end
+        if ~valid_flag1 then
+            break
+        end
+    end
+
+    valid_flag2 = (length( find(board) ) >= 17); //enforces rule of minimum of 17 givens
+                                                 //set it to always %T to ignore this rule
+    valid_board = (valid_flag1 & valid_flag2);
+
+    varargout=list(valid_board)
+endfunction
+
+disp('Initial board:');
+disp_board(Init_board);
+
+valid_init_board=validate_board(Init_board);
+
+if ~valid_init_board then
+    error('Invalid initial board. Should follow sudoku rules and have at least 17 clues.');
+end
+
+blank=[];
+for i=1:9
+    for j=1:9
+        if Init_board(i,j)== 0 then
+            blank=[blank; i j];
+        end
+    end
+end
+
+Solved_board=Init_board;
+
+tic();
+i=0; counter=0; breaked=%F;
+while i<size(blank,'r')
+    i=i+1;
+    counter=counter+1;
+    pos=blank(i,:);
+
+    value=Solved_board(pos(1),pos(2));
+
+    valid_value=%F;
+
+    while valid_value==%F
+        value=value+1;
+        if value>=10
+            break
+        else
+            valid_value=validate_input(value,pos,Solved_board);
+        end
+    end
+
+    if valid_value & value<10 then
+        Solved_board(pos(1),pos(2))=value
+    else
+        Solved_board(pos(1),pos(2))=0;
+        i=i-2;
+    end
+
+    if counter==break_point
+        breaked=%T;
+        break
+    end
+end
+
+valid_solved_board=validate_board(Solved_board);
+t2=toc();
+
+if valid_solved_board & ~breaked then
+    disp('Solved!');
+    disp('Solution:');
+    disp_board(Solved_board);
+    disp('Time: '+string(t2)+'s.');
+    disp('Steps: '+string(counter)+'.');
+elseif breaked
+    disp('Break point reached.');
+    disp('Time: '+string(t2)+'s.');
+    disp_board(Solved_board);
+elseif ~valid_solved_board & ~breaked
+    disp('Invalid solution found.');
+    disp_board(Solved_board);
+end