排序算法 很不错的 总结
http://blog.csdn.net/han_xiaoyang/article/details/12163251

查找算法 顺序表查找 二分查找 BST AVL
哈希表查找
http://blog.csdn.net/v_july_v/article/details/6256463

#include <stdio.h>
#include <stdlib.h>
#define NULLKEY -32768
typedef struct
{
int *addr;
int len; // 当前数据元素个数
}hashtable;
//typedef struct hashnode *hashtable;
int m; //总表长 全局变量
int init_hashtable(hashtable *H)//不是查找表，改变了表，就要用指针
{
int i;
m =12;
H->len = m;
H->addr = (int *)malloc(m*sizeof(int));
for(i=0;i<m;i++)
H->addr[i] = NULLKEY;
return 1;
}
int hash(int key)
{
return key%m; //除留余数法
}
int insert_talble(hashtable *H,int key)
{
int i;
if(H->len=0) return 0;
int value = hash(key);
while(H->addr[value]!=NULLKEY)//不为空 冲突了
value = (value+1)%m; //开放定址法解决冲突
H->addr[value] = key;
return 1;
}
int search_table(hashtable H,int key)
{
int i;
if(H.len=0) return 0;
int value = hash(key);
while(H.addr[value]!=key && H.addr[value]!=NULLKEY)//不是要找的值，或者存了个别的比如16冲突的值
{
value = (value+1)%m; //开放定址法解决冲突
if(H.addr[value] == NULLKEY || value==hash(key))
{
printf("find fail %d!\n",key);
return 0;
}
}
printf("find and the addr is:%d.\n",value);
}
void print_hashtable(hashtable H)
{
int i;
for(i=0;i<m;i++)
printf("%6d",H.addr[i]);
printf("\n");
}
int main()
{
hashtable H;
init_hashtable(&H);
insert_talble(&H,24);
print_hashtable(H);
insert_talble(&H,2);
print_hashtable(H);
insert_talble(&H,4);
print_hashtable(H);
insert_talble(&H,12);
print_hashtable(H);
search_table(H,4);
search_table(H,16);
return 0;
}

如果两个正数相加溢出，结果一定是负数；如果两个负数相加溢出，结果一定是正数；一正一负相加，无论结果是正是负都不可能溢出。（signed）
#include<stdio.h>
#include<stdlib.h>
#defineINT_MAX (2147483647) //(2^31-1)
#defineINT_MIN (-2147483648) //(-2^31)
//为什么上面不能用2^31这种格式呢 因为#define是按照字符串复制过去的 根本不会计算
int myatoi(constchar* str)
{
if(str == NULL) return 0;
const unsigned int maxTest = INT_MAX /10;
const unsigned int maxDigit = INT_MAX %10;
int sum = 0;
int sign = 0;
unsigned int digit;
while(*str == * *)
str++;
if(*str==*-*||*str==*+*)
{
if(*str==*-*)
sign = -1;
else
sign = 1;
str++;
}
while(*str >= *0* && *str<=*9*)
{
digit = *str - *0*;
printf("the digitis:%d.\n",digit);
if(sum>maxTest || (sum ==maxTest)&&(digit>maxDigit))
{
printf("hehe.\n");
return sign>0?INT_MAX:INT_MIN;
}
sum = sum*10 + digit;
printf("the sumis:%d.\n",sum);
str++;
}
return sum*sign;
}
intmain()
{
char str[] = " -2638";
printf("the str %s atoiis:%d.\n",str,myatoi(str));
return 0;
}

好人一路平安