# A simple Java Solution

• ``````public class Solution {
public int findBlackPixel(char[][] picture, int N) {
int ans = 0;
int r = picture.length;
int c = picture[0].length;

int[][] data = new int[r][c];

int[] row = new int[r];
int[] col = new int[c];
HashMap<ArrayList<Integer>,Integer> map = new HashMap<ArrayList<Integer>,Integer>();
for(int i=0;i<r;i++){
int sum = 0;
ArrayList<Integer> list = new ArrayList<Integer>();
for(int j=0;j<c;j++){
if(picture[i][j] == 'W'){
data[i][j] = 0;
sum += 0;
}else{
sum += 1;
data[i][j] = 1;
}

}
row[i] = sum;
if(sum == N)
if(map.containsKey(list)){
map.put(list,map.get(list)+1);
}else{
map.put(list,1);
}
}

for(int i=0;i<c;i++){
int sum = 0;
for(int j=0;j<r;j++){
if(data[j][i] == 0){
sum += 0;
}else{
sum += 1;
}
}

col[i] = sum;
}

for(ArrayList<Integer> key : map.keySet()){
if((int)map.get(key) != N){
continue;
}

int k = 0;
for(int i=0;i<c;i++){
if(key.get(i) == 1 && col[i] == N){
k++;
}
}

ans += k * N;
}

return ans;
}
}

``````

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