数据结构⑦ 查找（线性表）-优快云博客

本文链接：https://blog.youkuaiyun.com/m0_73354184/article/details/128860618

基本概念

研究重点：

怎么存，怎么加约束关系，怎么提高查找效率

线性表

顺序查找（线性查找）

Squential Search Table 顺序查找表

代码实现

静态无序

typedef struct{
	int key;
    int information;
}ElemType;

typedef struct{
	ElemType *R;
	int length;
}SSTable;

int Search_Seq(SSTable ST , int key){
	ST.R[0].key = key;
	int i = ST.length;
	for(; ST.R[i].key != key ; i--);
	return i;
}

复杂度分析

折半查找（二分or对分查找）

代码实现

非递归

typedef struct{
	int key;
	int information;
}ElemType;

typedef struct{
	ElemType *R;
	int length;
}SSTable;

int Search_Bin(SSTable ST , int key){
	int low = 1 , high = ST.length;
	while(low <= high){
		int mid = (low + high) / 2;
		if(ST.R[mid].key == key){
			return mid;
		}else if(key < ST.R[mid].key){
			high = mid - 1;
		}else{
			low = mid + 1;
		}
	}
	return 0;
}

递归

typedef struct{
	int key;
	int information;
}ElemType;

typedef struct{
	ElemType *R;
	int length;
}SSTable;

int Search_Bin(SSTable ST , int key , int low , int high){
	if(low > high)	return 0;
	int mid = (low + high) / 2;
	if(key == ST.R[mid].key){
		return mid;
	}else if(key < ST.R[mid].key){
		Search_Bin(ST , key , low , mid - 1);
	}else{
		Search_Bin(ST , key , mid + 1 , high);
	}	
}