折半查找

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1.折半查找的非遞歸算法

int BinarySearch(SeqList &L,DataType x)
{
  int high=L.n-1,low=0,mid;
  while(low<=high){
    mid=(low+high)/2;
    if(x.key>L.data[mid].key) low=mid+1;
    else if(x.key<L.data[mid].key high=mid-1;
    else return mid;
  }
return -1;
};

2.折半查找的遞歸算法

int BinarySearchRecur(SeqList& L,DataType x,int low,int high){
	int mid=-1;
	if(low<=high){
		mid=(low+high)/2;
		if(x.key>L.data[mid].key)
			mid=BinarySearchRecur(L,x,mid+1,high);
		else if(x.key<data[mid].key)
			mid=BinarySearchRecur(l,x,low,mid-1);

	}
	return mid;
};