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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <iostream>
#include <queue>
#include <unordered_map>
#include <cmath>
#include <queue>
#include <string>
using namespace std;
typedef long long ll;
const int maxn = 405;

int n,m;
string s[maxn];
int dir[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
int nb, nw;
bool f[maxn][maxn];

void bfs(int x, int y) {
  nb = nw = 0;
  queue<int>qx,qy;
  qx.push(x);
  qy.push(y);
  f[x][y] = 1;
  while(!qx.empty()) {
    int x = qx.front();
    qx.pop();
    int y = qy.front();
    qy.pop();
    if(s[x][y]=='#')nb++;
    else nw++;
    for(int i =0;i<4;i++){
      int nx = x+dir[i][0];
      int ny = y+dir[i][1];
      if(nx<0||nx>=n||ny<0||ny>=m)continue;
      if(f[nx][ny])continue;
      if(s[nx][ny]!=s[x][y]){
        f[nx][ny]=1;
        qx.push(nx);
        qy.push(ny);
      }
    }
  }
}

int main() {
#ifdef suiyuan2009
  freopen("/Users/suiyuan2009/CLionProjects/icpc/input.txt", "r", stdin);
  //freopen("/Users/suiyuan2009/CLionProjects/icpc/output.txt", "w", stdout);
#endif
  cin>>n>>m;
  for(int i=0;i<n;i++)cin>>s[i];
  ll ret = 0;
  for(int i=0;i<n;i++)
    for(int j=0;j<m;j++){
      if(s[i][j]=='#'&&f[i][j]==0){
        bfs(i,j);
        ret += nb * (ll)nw;
      }
    }
  cout<<ret<<endl;
  return 0;
}