Problem:
Score : 300 points

Problem Statement

There is a grid with H rows and W columns, where each square is painted black or white.

You are given H strings S_1, S_2, ..., S_H, each of length W.
If the square at the i-th row from the top and the j-th column from the left is painted black, the j-th character in the string S_i is #; if that square is painted white, the j-th character in the string S_i is ..

Find the number of pairs of a black square c_1 and a white square c_2 that satisfy the following condition:

There is a path from the square c_1 to the square c_2 where we repeatedly move to a vertically or horizontally adjacent square through an alternating sequence of black and white squares: black, white, black, white...

Constraints

1 \leq H, W \leq 400

|S_i| = W (1 \leq i \leq H)

For each i (1 \leq i \leq H), the string S_i consists of characters # and ..

Input

Input is given from Standard Input in the following format:

H W
S_1
S_2
:
S_H

Output

Print the answer.

Sample Input 1

3 3
.#.
..#
#..

Sample Output 1

10

Some of the pairs satisfying the condition are ((1, 2), (3, 3)) and ((3, 1), (3, 2)), where (i, j) denotes the square at the i-th row from the top and the j-th column from the left.

Sample Input 2

2 4
....
....

Sample Output 2

0

Sample Input 3

4 3
###
###
...
###

Sample Output 3

6

Solution in C (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <stdio.h>

int root_check(int h, int w, char s[h][w+1], int start_x, int start_y, int gole_x, int gole_y, int visit[h][w+1]){
   
    if(visit[start_x][start_y])
        return 0;
    visit[start_x][start_y] = 1;
    if(start_x == gole_x && start_y == gole_y)
        return 1;
    if(start_x > 0 && s[start_x][start_y] != s[start_x-1][start_y]){
        if(root_check(h, w, s, start_x-1, start_y, gole_x, gole_y, visit))
            return 1;
    }
    if(start_x < h-1 && s[start_x][start_y] != s[start_x+1][start_y]){
        if(root_check(h, w, s, start_x+1, start_y, gole_x, gole_y, visit))
            return 1;
    }
    if(start_y > 0 && s[start_x][start_y] != s[start_x][start_y-1]){
        if(root_check(h, w, s, start_x, start_y-1, gole_x, gole_y, visit))
            return 1;
    }
    if(start_y < w-1 && s[start_x][start_y] != s[start_x][start_y+1]){
        if(root_check(h, w, s, start_x, start_y+1, gole_x, gole_y, visit))
            return 1;
    }
    return 0;
}

int black_white(int h, int w, char s[h][w+1], int x, int y){
    int count = 0;
    int i, j;
    int visit[h][w+1];

    for(i = 0; i < h;i++){
        //printf("\n");
        for(j = 0; j < w; j++){
           // printf("%c", s[i][j]);
            if(s[i][j] == '.'){
               // printf("%d %d\n", i,j);
                for(int a=0;a<h;a++)
                    for(int b=0;b<=w; b++)
                        visit[a][b] = 0;    
                count += root_check(h, w, s, x, y, i, j, visit);
               // printf("(%d %d)(%d %d) %d\n",x, y,i,j,count);
            }
        }
    }
    return count;
}

int count_root(int h, int w, char s[h][w+1]){
    int i, j, count = 0;
    for(i = 0; i < h;i++){
        for(j = 0; j < w; j++){
            if(s[i][j] == '#'){
                count += black_white(h, w, s, i, j);
            }
        }
    }

    return count;
}

int main(){
    int h, w, i;
    scanf("%d%d", &h, &w);
    char s[h][w+1];
    
    for(i = 0; i < h; i++){
        scanf("%s", s[i]);
    }
    int black;

    printf("%d\n",count_root(h, w, s));
    return 0;
}