class Solution { public: bool Find(int target, vector<vector<int> > array) { int i = 0; int j = array[0].size()-1; while(i<array.size() && j>=0){ if(target > array[i][j]){ i++; } else if (target < array[i][j]){ j--; } else{ return true; } } return false; } };从右上或者左下去二分寻找