剑指offer 代码

1.赋值运算符

class cmystring{public:cmystring (char *pData = NULL);cmystring (const cmystring& str);~cmystring(void);private:char *m_pData;}//赋值运算符cmystring& cmystring::operator = (const cmystring &str){if(this == &str)return *this;delete []m_pData;m_pData = NULL;m_pData = new char[strlen(str.m_pData)+1];strcpy(m_pData,str.m_pData);return *this;}

2.单例模式

class CSingleton{private:CSingleton(){}static CSingleton *m_pInstance;class CGarbo{public:~CGarbo(){if(CSingleton::m_pInstance)delete CSingleton::m_pInstance;}};static CGarbo Garbo;public:static CSingleton *GetInstance(){if(m_pInstance == NULL)m_pInstance = new CSingleton();return m_pInstance;}};

3.二维数组查找

bool Find(int *m,int rows,int columns,int number){bool found = false;if(m!=NULL&&rows>0&&columns>0){int row = 0;int column = columns - 1;while(row <rows &&column>=0){if(m[row*columns+column] == number){found = true;break;}else if (m[row*columns+column]>number)--column;elserow++;}}return found;}

4.替换空格

void RepalceBlank(char string[],int length){if(string == NULL && length <= 0)return;int originalLength = 0;int numberOfBlank = 0;int i = 0;while(string[i]!='\0'){++originalLength;if(string[i] == ' ')++numberOfBlank;++i;}int newLength = originalLength + numberOfBlank * 2;if (newLength > length)return;int indexOfNew = newLength;int indexOfOriginal = originalLength;while(indexOfOriginal >= 0&& indexOfNew > indexOfOriginal){if(string[indexOfOriginal] ==' '){string[indexOfNew--] = '0';string[indexOfNew--] = '2';string[indexOfNew--] = '%';}elsestring[indexOfNew--] = string[indexOfOriginal];indexOfOriginal--;}}

5.从尾到头打印链表

struct ListNode{int m_key;ListNode *m_next;};void PrintListReverse(ListNode* pHead){stack<ListNode*> nodes;ListNode* pNode = pHead;while(pNode!=NULL){nodes.push(pNode);pNode = pNode->m_next;}while(!nodes.empty()){pNode = nodes.top();nodes.pop();}}

6.O(l)删除链表的结点

void DeleteNode(ListNode **pListHead,ListNode *pDeleted){if(!pListHead || !pDeleted)return;if(pDeleted->m_next!=NULL){ListNode *pNext = pDeleted->m_next;pDeleted->m_key = pNext->m_key;pDeleted->m_next = pNext->m_next;delete pNext;pNext = NULL;}else if(*pListHead == pDeleted){delete pDeleted;pDeleted = NULL;*pListHead = NULL;}else{ListNode* pNode = *pListHead;while(pNode->m_next!=pDeleted)pNode = pNode->m_next;pNode->m_next = NULL;delete pDeleted;pDeleted = NULL;}}

7.树的子树

struct TreeNode{int value;TreeNode* left;TreeNode* right;}bool HasSubtree(TreeNode *r1,TreeNode *r2){bool result = false;if(r1!=NULL&&r2!=NULL){if(r1->value == r2->value)result = DoesTree1HaveTree2(r1,r2);if(!result)result = HasSubtree(r1->left,r2);if(!result)result = HasSubtree(r1->right,r2);}return result;}bool DoesTree1HaveTree2(TreeNode* r1,TreeNode* r2){if(r2==NULL)return true;if(r1==NULL)return false;if(r1->value!=r2->value)return false;return DoesTree1HaveTree2(r1->left,r2->left)&&DoesTree1HaveTree2(r1->right,r2->right);}

8.层次遍历

void printtree(TreeNode* pTreeRoot){if(!pTreeRoot)return;deque<TreeNode*> dequeTreeNode;dequeTreeNode.push_back(pTreeRoot);while(dequeTreeNode.size()){TreeNode *pNode = dequeTreeNode.front();dequeTreeNode.pop_front();printf("%d ",pNode->value);if(pNode->left)dequeTreeNode.push_back(pNode->left);if(pNode->right)dequeTreeNode.push_back(pNode->right);}}

9.数组中出现次数超过一半

int MoreThanHalfNum(int* numbers, int length){if(numbers == NULL && length <= 0)return;int result = numbers[0];int times = 1;for(int i = 1; i < length; ++i){if(times == 0){result = numbers[i];times = 1;}else if (numbers[i] == result)times++;elsetimes--;}return result;}

10.最小k个数

int Partition(int data[],int length,int start, int end){if(data == NULL ||length <= 0 || start < 0 || end >= length)throw new std::exception("invalid parameters");int index = RandomInRange(start,end);swap(&data[index],&data[end]);int small = start -1;for(index = start;index<end;++index){if(data[index]<data[end]){small++;if(small != index)swap(&data[index],&data[small]);}}small++;swap(&data[small],&data[end]);return small;}void GetLeastNumbers(int *input,int n,int *output,int k){if(input == NULL || output == NULL || k > n || n<= 0 || k<=0)return;int start = 0;int end = n - 1;int index = Partition(intput, n , start , end);while(index != k-1){if(index > k-1){end = index - 1;index = Partition(input,n,start,end)'}else{start = index+1;index = Partition(input,n,start,end);}}for(int i = 0;i<k;i++)output[i] = input[i];}

11.连续子数组的最大和

int FindGreatestSumOfSubArray(int *pData,int nLength){if((pData == NULL) || (nLength <= 0))return;int nCurSum = 0;int nGreatestSum = 0x80000000;for(int i = 0; i < nLength ; ++i){if(nCurSum <= 0)nCurSum = pData[i];elsenCurSum += pData[i];if(nCurSum > nGreatestSum)nGreatestSum = nCurSum;}return nGreatestSum;}

12.字符串中第一个出现一次的字符

char FirstNotRepeatingChar(char* pString){if(pString == NULL)return '\0';const int tableSize = 256;unsigned int hashTable[tableSize];for(unsigned int i = 0; i < tableSize; ++i)hashTable[i] = 0;char* pHashKey = pString;while(*(pHashKey)!='\0')hashTable[*(pHashKey++)]++;pHashKey = pString;while(*pHashKey != '\0'){if(hashTable[*pHashKey] == 1)return *pHashKey;pHashKey++;}return '\0';}

13.两个链表的第一个公共交点

int GetListLength(ListNode *pHead){unsigned int length = 0;ListNode *p = pHead;while(p!=NULL){length++;p = p->m_next;}return length;} ListNode *FindFirstCommonNode(ListNode *pHead1,ListNode *pHead2) { unsigned int nLength1 = GetListLength(pHead1); unsigned int nLength2 = GetListLength(pHead2); int nLengthDif = nLength1 - nLength2; ListNode* pListHeadLog = pHead1; ListNode* pListHeadShort = pHead2; for(int i = 0;i < nLengthDif;i++) pListHeadLog = pListHeadLog ->m_next; while((pListHeadLog!=NULL)&&(pListHeadShort!=NULL)&&(pListHeadLog!=pListHeadShort)) { pListHeadLog = pListHeadLog ->m_next; pListHeadShort = pListHeadShort->m_next; } ListNode *pFirstCommonNode = pListHeadLog; return pFirstCommonNode; }

14.数组中出现次数为1的数字

 void FindNumsAppearOnce(int data[],int n) { int result = 0; for(int i = 0;i<n;i++) result^=data[i]; int t; for(t=1;t<result;t++) { if(t&result) break; } int a=0,b=0; for(int i = 0;i < n; i++) { if(t&data[i]) a^=data[i]; else b^=data[i]; } printf("%d %d\n",a,b); }

15.数组中两个数之和为一定值

 bool FindNumbersWithSum(int data[],int length,int sum,int *num1,int *num2) { bool found = false; if(length < 1 || num1 == NULL || num2 == NULL) return found; int ahead = length - 1; int behind = 0; while(ahead > behind) { long long curSum = data[ahead]+data[behind]; if(curSum == sum) { *num1 = data[behind]; *num2 = data[ahead]; found = true; break; } else if(curSum > sum) ahead--; else behind++; } return found; }

16.翻转单词

 void Reverse(char *pBegin,char *pEnd) { if(pBegin == NULL || pEnd == NULL) return; while(pBegin < pEnd) { char temp = *pBegin; *pBegin = *pEnd; *pEnd = temp; pBegin ++; pEnd--; } } char *ReverseSentence(char *pData) { if(pData == NULL) return NULL; char *pBegin = pData; char *pEnd = pData; while(*pEnd !='\0') pEnd++; pEnd--; Reverse(pBegin,pEnd); pBegin = pEnd = pData; while(*pBegin!='\0') { if(*pBegin ==' ') { pBegin++; pEnd++; } else if(*pEnd ==' ' || *pEnd == '\0') { Reverse(pBegin,--pEnd); pBegin = ++pEnd; } else pEnd++; } return pData; }

17.约瑟夫环

int LastRemaining(unsigned int n, unsigned int m){if(n<1||m<1)return -1;unsigned int i = 0;list<int> numbers;for(i = 0;i<n;i++)numbers.push_back(i);list<int>::iterator current = numbers.begin();while(numbers.size() > 1){for(int i = 1;i<m;++i){current++;if(current == numbers.end())current = numbers.begin();}list<int>::iterator next = ++current;if(next == numbers.end())next = numbers.begin();--current;numbers.erase(current);current = next;}return *(current);}