剑指 Offer 04. 二维数组中的查找

public class offer04 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int[][] matrix = new int[][]{
                                     {1,   4,  7, 11, 15},
                                     {2,   5,  8, 12, 19},
                                     {3,   6,  9, 16, 22},
                                     {10, 13, 14, 17, 24},
                                     {18, 21, 23, 26, 30}
        };
        int target = 20;
        System.out.println(findNumberIn2DArray(matrix,target));

    }
    
    public static boolean findNumberIn2DArray(int[][] matrix, int target) {
        if(matrix==null||matrix.length==0||matrix[0].length==0){
            return false;
        }
        int rows = matrix.length;
        int cols = matrix[0].length;
        
        int i = 0,j = cols-1;
        while(matrix[i][j]!=target){
            if(matrix[i][j]>target){
                j = j-1;
            }else if(matrix[i][j]<target){
                i = i+1;
            }
            if(i>=rows||j<0){//当i或者j超出边界时，说明没有找到，返回false
                return false;
            }
            //System.out.println("i："+i+",j:"+j+",matrix:"+matrix[i][j]);
        }
        
        return true;
    }

}