【劍指offer】 第三題 二維陣列查詢

package javaTrain;

public class offer3 {
	public static void main(String args[]) {
		 int[][] a = {{0,1,2,3},{1,2,3,4},{2,3,4,5},{6,7,8,9}};
		 System.out.println(find(a,10));
	}
	public static boolean find(int[][] a,int num) {
		if(a == null) return false;
		
		int n = a.length;
		int m = a[0].length;
		int i = 0;
		int j = m-1;
		while(i < n && j >= 0) { 
			if(a[i][j] == num) return true;
			else if(a[i][j] > num) --j;
			else ++i;
		}
		
		return false;
	}
}