int lengthOfLcs_r(const char x[], const char y[], int ix, int iy, int xsize, int ysize) {
static int **lengthTable = new int*[xsize];
for (int i = 0; i < xsize; ++i) {
lengthTable[i] = new int[ysize];
}

if (ix == xsize || iy == ysize) {
return 0;
}
if (x[ix] == y[iy]) {
return lengthOfLcs_r(x, y, ix + 1, iy + 1, xsize, ysize) + 1;
}
return max(lengthOfLcs_r(x, y, ix, iy + 1, xsize, ysize), lengthOfLcs_r(x, y, ix + 1, iy, xsize, ysize));
}