[문제요약] * 는 아래 ,위, 좌,우 로 연결되어 있으면 하나의 블럭으로 간주한다. 블럭수을 구하는게 문제이다.
Bessie is piloting the craft through this treacherous N x N (1 <= N <= 1,000) sector of space. Asteroids in this sector comprise some number of 1 x 1 squares of space-rock connected along their edges (two squares sharing only a corner count as two distinct asteroids). Please help Bessie maneuver through the field by counting the number of distinct asteroids in the entire sector.
Consider the 10 x 10 space shown below on the left. The '*'s represent asteroid chunks, and each '.' represents a .vast void of empty space. The diagram on the right shows an arbitrary numbering applied to the asteroids.
...**..... ...11..... .*........ .2........ ......*... ......3... ...*..*... ...3..3... ..*****... ..33333... ...*...... ...3...... ....***... ....444... .*..***... .5..444... .....*...* ......4...6 ..*....... ..7........It's easy to see there are 7 asteroids in this sector.
입력 10 ...**..... .*........ ......*... ...*..*... ..*****... ...*...... ....***... .*..***... .....*...* ..*....... 출력 7
출처:usaco 2011 JAN bronze