lintcode ----二分查找

int binarySearch(vector<int> &array, int target)   {  // write your code here  int start=0,end=array.size()-1;  while(start<end)  {  int mid=start+(end-start)/2;  if(array[mid]<=target)  {  start=mid+1;  }  else if(array[mid]>target)  {  end=mid-1;  }  else   end=mid;  }  if(array[end]==target)  return end;  return -1;  }