集合栈-程序员面试金典

数据结构由多个栈组成，用链表连接，并且在前一个栈填满之时，新建一个栈，且push（）方法和pop（）方法和top（）方法与普通栈的方法一样。且实现了一个popAt（int index）方法,指定子栈，并执行pop（）操作，当一个非最后的栈pop时，用后续栈将其填满。为实现popAt（）需要访问后一个栈的底部，所以不能使用Stack模板，而是使用deque。pop（），push（），top（）都是通过back而访问底部（bottom）则是通过front。链表结点的创建用CreateListNode(deque<int> value)删除用RemoveNode(ListNode** pHead, deque<int> value)。

代码如下：

#include<iostream>#include<deque>using namespace std;struct ListNode{deque<int> m_nValue;ListNode* m_pNext;};ListNode* CreateListNode(deque<int> value){ListNode* pNode = new ListNode();pNode->m_nValue = value;pNode->m_pNext = NULL;return pNode;}void ConnectListNodes(ListNode* pCurrent, ListNode* pNext){if (pCurrent == NULL){printf("Error to connect two nodes.\n");exit(1);}pCurrent->m_pNext = pNext;}void PrintListNode(ListNode* pNode){if (pNode == NULL){printf("The node is NULL\n");}else{printf("The key in node is %d.\n", pNode->m_nValue);}}void PrintList(ListNode* pHead){printf("PrintList starts.\n");ListNode* pNode = pHead;while (pNode != NULL){printf("%d\t", pNode->m_nValue);pNode = pNode->m_pNext;}printf("\nPrintList ends.\n");}void DestroyList(ListNode* pHead){ListNode* pNode = pHead;while (pNode != NULL){pHead = pHead->m_pNext;delete pNode;pNode = pHead;}}void AddToTail(ListNode** pHead, deque<int> value){ListNode* pNew = new ListNode();pNew->m_nValue = value;pNew->m_pNext = NULL;if (*pHead == NULL){*pHead = pNew;}else{ListNode* pNode = *pHead;while (pNode->m_pNext != NULL)pNode = pNode->m_pNext;pNode->m_pNext = pNew;}}void RemoveNode(ListNode** pHead, deque<int> value){if (pHead == NULL || *pHead == NULL)return;ListNode* pToBeDeleted = NULL;if ((*pHead)->m_nValue == value){pToBeDeleted = *pHead;*pHead = (*pHead)->m_pNext;}else{ListNode* pNode = *pHead;while (pNode->m_pNext != NULL && pNode->m_pNext->m_nValue != value)pNode = pNode->m_pNext;if (pNode->m_pNext != NULL && pNode->m_pNext->m_nValue == value){pToBeDeleted = pNode->m_pNext;pNode->m_pNext = pNode->m_pNext->m_pNext;}}if (pToBeDeleted != NULL){delete pToBeDeleted;pToBeDeleted = NULL;}}int length(ListNode* head){if (head == NULL)return 0;ListNode* n = head;int count = 1;while (n->m_pNext != NULL){n = n->m_pNext;++count;}return count;}ListNode* get(ListNode* head,int n){if (n < 0||head==NULL)return NULL;int count = 0;ListNode* node = head;while (node->m_pNext != NULL&&n!=count){node = node->m_pNext;++count;}if (node->m_pNext == NULL&&n!= count){cout << "n>length error" << endl;return NULL;}return node;}class SetOfStacks{public:ListNode* stacks;int capacity;SetOfStacks(int c) :capacity(c){ stacks = NULL; }~SetOfStacks(){};ListNode* getLastStack(){if (stacks == NULL)return NULL;return get(stacks, length(stacks)-1);}void push(int v){if (getLastStack() == NULL){deque<int> stack;stack.push_back(v);ListNode* outset = CreateListNode(stack);stacks = outset;return;}deque<int>& last = getLastStack()->m_nValue;if (getLastStack() != NULL&&!(last.size() == capacity)){last.push_back(v);}else{deque<int> stack;stack.push_back(v);ListNode* another= CreateListNode(stack);ConnectListNodes(getLastStack(), another);}}void pop(){deque<int>& last = getLastStack()->m_nValue;last.pop_back();if (last.size() == 0)RemoveNode(&stacks, last);}int top(){return getLastStack()->m_nValue.back();}bool Empty(){deque<int> last = getLastStack()->m_nValue;return (getLastStack() == NULL) || last.empty();}int leftShift(int index,bool removeTop){deque<int>& stack = get(stacks, index)->m_nValue;int removed_item;if (removeTop){removed_item = stack.back();stack.pop_back();}else{removed_item = stack.front();stack.pop_front();}if (stack.empty())RemoveNode(&stacks, stack);else if (length(stacks) > index + 1){int v = leftShift(index + 1, false);stack.push_back(v);}return removed_item;}int popAt(int index){return leftShift(index, true);}};int main(){SetOfStacks s(3);s.push(1); s.push(2); s.push(3); s.push(4); s.push(5); s.push(6);cout << s.popAt(0) << endl;cout << s.popAt(0) << endl;cout << s.top() << endl;s.pop();cout << s.top() << endl;s.pop();cout << s.top() << endl;s.pop();cout << s.top() << endl;s.pop();cin.get();return 0;}

最后，心得：一定要记得引用啊！一定要记得引用啊！一定要记得引用啊！重要的话说三遍，它不是Java，没有引用就是传递临时对象了。

最近频频转换java和C++，头都乱了。。。

这是结果，嗯嗯。

吃饭去了。