C :

#include<stdio.h>
#include<math.h>

#define N 200


void fun(char* s, int *red, int *green, int *blue)
{
	int  t; 
	for (int i = 0; s[i]; i++) 
	{ 
		if (i>= 1 && i <= 2)
		{
			if (s[i] <= '9')
				t = s[i] - '0';
			else t = s[i] - 'A' + 10;
			*red = *red * 16 + t;
		}
		if (i<=4 && i>2)
		{
			if (s[i] <= '9')
				t = s[i] - '0';
			else t = s[i] - 'A' + 10;
			*green = *green * 16 + t;
		}
		if (i<=6 && i>4)
		{
			if (s[i] <= '9')
				t = s[i] - '0';
			else t = s[i] - 'A' + 10;
			*blue = *blue * 16 + t;
		}
		
	}
}

float huiduzhi(int red,int green,int blue)
{
	float huiduzhi;
	huiduzhi = (11 * red + 16 * green + 5 * blue) / 32;
	return huiduzhi;
}

char a[N][N][N];

int main()
{
	int i, j, w, h, hdz[N][N];
	while (scanf("%dx%d", &w, &h) != EOF)
	{
		for (i = 0; i < h; i++)
		for (j = 0; j < w; j++)
		{
			scanf("%s", a[i][j]);
		}
		int sum = 0;
		for (i = 0; i < h; i++)
		{
			for (j = 0; j < w; j++)
			{
				int red = 0, green = 0, blue = 0;
				fun(a[i][j], &red, &green, &blue);
				hdz[i][j] = huiduzhi(red, green, blue);
			}
		}
		for (i = 0; i < h; i++)
		for (j = 0; j < w; j++)
			sum = sum + hdz[i][j];
		float yuzhi;
		yuzhi = (192 + 2 * (sum / (w*h))) / 3;
		printf("%dx%d\n", w, h);
		for (i = 0; i < h; i++)
		{
			for (j = 0; j < w; j++)
			{
				if (hdz[i][j] < yuzhi)
				{
					if (j != w-1)
						printf("9 ");
					else
						printf("9");
				}
				else
				{
					if (j != w-1)
						printf("  ");
					else
						printf(" ");
				}
			}
			printf("\n");
		}
	}
	return 0;
}

C++ :

#include <stdio.h>
int main ()
{
	int w, h, i, j;
	int a[500];
	int map[301][301];
	char c, str[20];

	for(i = 0 ; i < 11 ; i ++)
	{
		a['0' + i] = i;
		a['A' + i] = 10 + i;
	}
	while(scanf("%d%c%d",&w,&c,&h) != EOF)
	{
		int sum = 0;
		for(i = 0 ; i < h ; i ++)
		{
			for(j = 0 ; j < w ; j ++)
			{
				scanf("%s",str);
				int r = a[(int)str[1]] * 16 + a[(int)str[2]];
				int g = a[(int)str[3]] * 16 + a[(int)str[4]];
				int b = a[(int)str[5]] * 16 + a[(int)str[6]];
				map[i][j] = (11 * r + 16 * g + 5 * b) / 32;
				sum += map[i][j];
			}
		}
		
		int average_grayscale = sum / (w * h);
		int formala = (192 + 2 * average_grayscale) / 3;
		printf("%dx%d\n",w,h);
		for(i = 0 ; i < h ; i ++)
		{
			for(j = 0 ; j < w ; j ++)
			{
				if(j)
					printf(" ");
				if(map[i][j] < formala)
					printf("9");
				else
					printf(" ");
				
			}
			printf("\n");
		}
	}
	return 0;
}