对称大法解题范例【2011】四、1

【2011】四、1（子矩阵）输入一个n1*m1的矩阵a，和n2*m2的矩阵b，问a中是否存在子矩阵和b相等。若存在，输出所有子矩阵左上角的坐标；若不存在输出“there
is no answer”。

 

const

    size = 50;

var

    n1, m1, n2, m2, i, j, k1, k2 :integer;

    a, b : array[1..size, 1..size] of integer;

    good, haveans : boolean;

begin

    readln(n1, m1);

    for i := 1 to n1 do

        for j := 1 to m1 do

            read(a[i][j]);

    readln(n2, m2);

    for i := 1 to n2 do

        for j := 1 to m2 do

                ①    ;

    haveans := false;

    for i := 1 to n1 - n2 + 1 do

        for j := 1 to     ②     do

        begin

                ③    ;

            for k1 := 1 to n2 do

                for k2 := 1 to     ④     do

                    if a[i + k1 - 1][j + k2 -1] <> b[k1][k2] then

                        good := false;

            if good then

            begin

                writeln(i, ' ', j);

                    ⑤    ;

            end;

        end;

    if not haveans then

        writeln('there is no answer');

end.

 

①    向前4行，read(b[i][j]);

②    向前1行，m1 - m2 + 1

③    向后4行，good := true

④    向前1行，m2

⑤    向前12行，haveans := true