23. Search a 2D Matrix II

class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        int r = 0, c = matrix[0].length-1;
        while(r < matrix.length && c >= 0) {
            if(matrix[r][c] == target) return true;
            else if(matrix[r][c] < target) r++;
            else c--;
        }
        return false;
    }
}