gistfile1.matlab

function [Result ResultSudoku] = ResolveSudoku(InputSudoku)
	A = [1 2 3 4 5 6 7 8 9];
	B = [1 2 3 4 4 5 5 6 6 7 7 7 8 8 8 9 9 9];
	C = [1 2 2 3 3 3 4 5 5 6 6 6 7 8 8 9 9 9];
	f = @(x) sum(sum(power(2,x))) / 1022;
	g = @(m,r,c) [m(3*r-2,3*c-2:3*c) m(3*r-1,3*c-2:3*c) m(3*r,3*c-2:3*c)];
	j = @(m,r,c) g(m,sum(B == r),sum(B == c));
	h = @(m,r,c) intersect(intersect(setdiff(A,m(r,:)),setdiff(A,m(:,c))),setdiff(A,j(m,r,c)));
    function [R RS] = Resolve(IS,ESC)
        if ESC == 0
            for n = 1:9
                r = sum(B == n); l = sum(C == n);
                if sum([f(IS(n,:)) f(IS(:,n)) f(IS(3*r-2:3*r,3*l-2:3*l))]) ~= 3
                    R = 0; return;
                end
            end
            RS = IS; R = 1;
        else
            a = 1; [rs, cs] = find(IS == 0);
            while a ~= 0
                a = 0;
                for n = 1:ESC
                    D = h(IS,rs(n),cs(n));
                    if length(D) == 1
                        IS(rs(n),cs(n)) = D(1);
                        a = a + 1;
                    end
                end
                [rs, cs] = find(IS == 0); ESC = length(rs);
            end
            if ESC == 0
                R = 1; RS = IS;
            else
                D = h(IS,rs(1),cs(1));
                for n = 1:length(D)
                    IS(rs(1),cs(1)) = D(n);
                    [R RS] = Resolve(IS,ESC - 1);
                    if R == 1
                        return
                    end
                end
                R = 0; IS(rs(1),cs(1)) = 0; RS = IS; return
            end
        end
    end
	function R = IsSudokuCandidate(IS)
		R = 1;
		for n = 1:9
			r = sum(B == n); l = sum(C == n);
			P = [IS(n,:) IS(:,n)' [IS(3*r-2,3*l-2) IS(3*r-1,3*l-1) IS(3*r,3*l)]];
			for i = 1:3
				for j = 1:9 
					if sum( P(i) == A(j)) > 1
					   R = 0; return 
					end
				end
			end
		end
	end

if IsSudokuCandidate(InputSudoku) == 0
    Result = 0; ResultSudoku = InputSudoku; 
	return
end
	[Result ResultSudoku] = Resolve(InputSudoku,length(find(InputSudoku == 0)));
end