两次二分，一次AC，注意越界的问题。

using namespace std;
class Solution {
public:
    bool searchMatrix(vector<vector<int> > &matrix, int target) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if(matrix.size() <= 0)
            return false;
        if(target > matrix[matrix.size()-1][matrix[0].size()-1])
            return false;
        vector<int>cols(matrix.size());
        for(int i = 0;i < matrix.size();i++)
        {
            cols[i] = matrix[i][matrix[0].size()-1];
        }
        int colindex = bsearch(0,(int)(matrix.size()),cols,target);
        if(colindex == -1)
            return true;
        int rowindex = bsearch(0,(int)(matrix[colindex].size()),matrix[colindex],target);
        if(rowindex == -1)
            return true;
        return false;
    }
    int bsearch(int left,int right,vector<int> seq,int target)
    {
        if(left > right)
        {
            return right + 1;
        }
        int mid = (left + right) / 2;
        if(seq[mid] == target)
        {
            return -1;
        }
        else
            if(seq[mid] < target)
            {
                return bsearch(mid+1,right,seq,target);
            }
            else
            {
                return bsearch(left,mid-1,seq,target);
            }
    }
};