Pretty straight-forward, perhaps I lucked out on the time of execution on the OJ (30ms)

```
public int findLonelyPixel(char[][] picture) {
if (picture == null || picture.length == 0 || picture[0].length == 0) return 0;
int m = picture.length, n = picture[0].length;
int[] rows = new int[m], cols = new int[n];
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (picture[i][j] == 'B') {
rows[i]++; cols[j]++;
}
}
}
int lonely = 0;
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (picture[i][j] == 'B' && rows[i] == 1 && cols[j] == 1) {
lonely++;
}
}
}
return lonely;
}
```