链表的颠倒算法

NO.10

用一种算法来颠倒一个链接表的顺序。现在在不用递归式的情况下做一遍。

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include

using namespace std;

struct node

{

int x;

node *next;

node()

{

x = 0;

next = NULL;

};

};

void make(node *head)

{

node *hea = head;

for(int i = 0;i<10;i++)

{

node *x = new node;

x->x= i;

hea->next = x;

hea = x;

}

};

void reverse(node *&head)

{

if(head->next == NULL)

return;

node *x = head;

head = head->next;

x->next = NULL;

while(NULL !=head)

{

node *y = head;

head = head->next;

y->next = x;

x = y;

}

head = x;

int i ;

};

int main()

{

node *head = new node;

//head->x = 4;

make(head);

reverse(head);

return 0;

}

而用递归方法实现的过程是：

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node* reverse2(node *oldhead,node *newhead = NULL )

{

node *next = oldhead->next;

oldhead->next = newhead;

newhead = oldhead;

return (NULL == next) ? newhead:reverse2(next,newhead);

};

（2） 颠倒一个字符串。优化速度。优化空间

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void reverseChar(char *str)

{

char *start = str;

int n = strlen(str);

char *p = str+n-1;

while(start < p)

{

char c = *start;

*start = *p;

*p=c;

start++;

p–;

}

}

（3）找到一个子字符串。优化速度。优化空间。

利用的Sunday算法

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int sunday(const char *src,const char *des)

{

int i,j,pos=0;

int len_s,len_d;

int next[26]={0}; //next数组，预处理初始化

len_s=strlen(src);

len_d=strlen(des);

for(j=0;j<26;++j) //初始化next数组

next[j]=len_d;

for(j=0;j