class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        int r=matrix.length, c = matrix[0].length;
        int start=0, end=r*c-1, mid=(start+end)/2;
        
        while(start<=end){
            if(matrix[mid/c][mid%c]>target)
                end=mid-1;
            else if(matrix[mid/c][mid%c]<target)
                start=mid+1;
            else
                return true;
            
            mid=(start+end)/2;
        }
        
        return false;
    }
}