本文涉及知识点
设计 数学 线段树
本文基础解法
LeetCode1622. 奇妙序列
请你实现三个 API append,addAll 和 multAll 来实现奇妙序列。
请实现 Fancy 类 :
Fancy() 初始化一个空序列对象。
void append(val) 将整数 val 添加在序列末尾。
void addAll(inc) 将所有序列中的现有数值都增加 inc 。
void multAll(m) 将序列中的所有现有数值都乘以整数 m 。
int getIndex(idx) 得到下标为 idx 处的数值(下标从 0 开始),并将结果对 109 + 7 取余。如果下标大于等于序列的长度,请返回 -1 。
示例:
输入:
[“Fancy”, “append”, “addAll”, “append”, “multAll”, “getIndex”, “addAll”, “append”, “multAll”, “getIndex”, “getIndex”, “getIndex”]
[[], [2], [3], [7], [2], [0], [3], [10], [2], [0], [1], [2]]
输出:
[null, null, null, null, null, 10, null, null, null, 26, 34, 20]
解释:
Fancy fancy = new Fancy();
fancy.append(2); // 奇妙序列:[2]
fancy.addAll(3); // 奇妙序列:[2+3] -> [5]
fancy.append(7); // 奇妙序列:[5, 7]
fancy.multAll(2); // 奇妙序列:[52, 72] -> [10, 14]
fancy.getIndex(0); // 返回 10
fancy.addAll(3); // 奇妙序列:[10+3, 14+3] -> [13, 17]
fancy.append(10); // 奇妙序列:[13, 17, 10]
fancy.multAll(2); // 奇妙序列:[132, 172, 10*2] -> [26, 34, 20]
fancy.getIndex(0); // 返回 26
fancy.getIndex(1); // 返回 34
fancy.getIndex(2); // 返回 20
提示:
1 <= val, inc, m <= 100
0 <= idx <= 105
总共最多会有 105 次对 append,addAll,multAll 和 getIndex 的调用。
线段树
由于最多105个元素,故线段树的元素个数105,初始全部为0。m_iSize记录已经插入的数据。
插入相当于对m_iSize单点更新(加法),乘和加相当于区域[0,m_iSize-1]更新。
std::pair记录更新的参数。first表示要乘的数,second 表示要加的数。两次操作合并的代码如下:
virtual void OnUpdateRecord(TRecord& old, const TRecord& newRecord) override { old.first *= newRecord.first; old.second = old.second * newRecord.first + newRecord.second; }
推导过程x先乘以a,加b;在乘以c,加d。
x1 = ax +b
x2 = axc + bc + d
相当于:x直接乘以 ab 后加bc+d。
代码
核心代码
template<int MOD = 1000000007> class C1097Int { public: C1097Int(long long llData = 0) :m_iData(llData% MOD) { } C1097Int operator+(const C1097Int& o)const { return C1097Int(((long long)m_iData + o.m_iData) % MOD); } C1097Int& operator+=(const C1097Int& o) { m_iData = ((long long)m_iData + o.m_iData) % MOD; return *this; } C1097Int& operator-=(const C1097Int& o) { m_iData = (m_iData + MOD - o.m_iData) % MOD; return *this; } C1097Int operator-(const C1097Int& o) { return C1097Int((m_iData + MOD - o.m_iData) % MOD); } C1097Int operator*(const C1097Int& o)const { return((long long)m_iData * o.m_iData) % MOD; } C1097Int& operator*=(const C1097Int& o) { m_iData = ((long long)m_iData * o.m_iData) % MOD; return *this; } bool operator==(const C1097Int& o)const { return m_iData == o.m_iData; } bool operator<(const C1097Int& o)const { return m_iData < o.m_iData; } C1097Int pow(long long n)const { C1097Int iRet = 1, iCur = *this; while (n) { if (n & 1) { iRet *= iCur; } iCur *= iCur; n >>= 1; } return iRet; } C1097Int PowNegative1()const { return pow(MOD - 2); } int ToInt()const { return m_iData; } private: int m_iData = 0;; }; template<class TSave, class TRecord> class CLineTree { public: CLineTree(int iEleSize, TRecord recordNull=0) :m_iEleSize(iEleSize), m_vArr(m_iEleSize * 4), m_vRecord(m_iEleSize * 4, recordNull), m_recordNull(recordNull) { } void Update(int iLeftIndex, int iRightIndex, TRecord value) { Update(1, 1, m_iEleSize, iLeftIndex + 1, iRightIndex + 1, value); } template<class TGet> void Query(const TGet& oGet, int iLeftIndex, int iRightIndex) { Query(oGet, 1, 1, m_iEleSize, iLeftIndex + 1, iRightIndex + 1); } private: virtual void OnUpdateRecord(TRecord& old, const TRecord& newRecord) = 0; virtual void OnUpdateParent(TSave& par, const TSave& left, const TSave& r) = 0; virtual void OnUpdate(TSave& save, const int& len, const TRecord& iUpdate) = 0; template<class TGet> void Query(const TGet& oGet, int iNode, int iSaveLeft, int iSaveRight, int iQueryLeft, int iQueryRight) { if ((iQueryLeft <= iSaveLeft) && (iQueryRight >= iSaveRight)) { oGet(m_vArr[iNode]); return; } Fresh(iNode, iSaveLeft, iSaveRight); const int iMid = iSaveLeft + (iSaveRight - iSaveLeft) / 2; if (iMid >= iQueryLeft) { Query(oGet, iNode * 2, iSaveLeft, iMid, iQueryLeft, iQueryRight); } if (iMid + 1 <= iQueryRight) { Query(oGet, iNode * 2 + 1, iMid + 1, iSaveRight, iQueryLeft, iQueryRight); } } void Update(int iNode, int iSaveLeft, int iSaveRight, int iOpeLeft, int iOpeRight, TRecord value) { if (iNode >= m_vArr.size()) { return; } if ((iOpeLeft <= iSaveLeft) && (iOpeRight >= iSaveRight)) { OnUpdate(m_vArr[iNode], min(iSaveRight, iOpeRight) - max(iSaveLeft, iOpeLeft) + 1, value); OnUpdateRecord(m_vRecord[iNode], value); return; } Fresh(iNode, iSaveLeft, iSaveRight); const int iMid = iSaveLeft + (iSaveRight - iSaveLeft) / 2; if (iMid >= iOpeLeft) { Update(iNode * 2, iSaveLeft, iMid, iOpeLeft, iOpeRight, value); } if (iMid + 1 <= iOpeRight) { Update(iNode * 2 + 1, iMid + 1, iSaveRight, iOpeLeft, iOpeRight, value); } // 如果有后代,至少两个后代 OnUpdateParent(m_vArr[iNode], m_vArr[iNode * 2], m_vArr[iNode * 2 + 1]); } void Fresh(int iNode, int iDataLeft, int iDataRight) { if (m_recordNull == m_vRecord[iNode]) { return; } const int iMid = iDataLeft + (iDataRight - iDataLeft) / 2; Update(iNode * 2, iDataLeft, iMid, iDataLeft, iMid, m_vRecord[iNode]); Update(iNode * 2 + 1, iMid + 1, iDataRight, iMid + 1, iDataRight, m_vRecord[iNode]); m_vRecord[iNode] = m_recordNull; } const int m_iEleSize; vector<TSave> m_vArr; vector<TRecord> m_vRecord; const TRecord m_recordNull; }; template<class TSave = C1097Int<>, class TRecord = pair<C1097Int<>,C1097Int<>> > class CMyLineTree : public CLineTree<TSave, TRecord> { public: using CLineTree<TSave, TRecord>::CLineTree; protected: virtual void OnUpdateRecord(TRecord& old, const TRecord& newRecord) override { old.first *= newRecord.first; old.second = old.second * newRecord.first + newRecord.second; } virtual void OnUpdateParent(TSave& par, const TSave& left, const TSave& r) override { } virtual void OnUpdate(TSave& save, const int& len, const TRecord& iUpdate) override { save = save * iUpdate.first + iUpdate.second; } }; class Fancy { public: Fancy() :m_lineTree(100'000, { 1,0 }) { } void append(int val) { m_lineTree.Update(m_iSize, m_iSize, { 1,val }); m_iSize++; } void addAll(int inc) { m_lineTree.Update(0, m_iSize - 1, { 1,inc }); } void multAll(int m) { m_lineTree.Update(0, m_iSize - 1, { m,0 }); } int getIndex(int idx) { if (idx >= m_iSize) { return -1; } C1097Int<> iiRet = 0; auto Get = [&](const C1097Int<>& value ) { iiRet += value; }; m_lineTree.Query(Get,idx,idx); return iiRet.ToInt(); } CMyLineTree<> m_lineTree; int m_iSize=0; };
旧代码
旧类库,将TRecord 的默认值 设计成参数,编辑器对次有限制。改成成员变量。
template class C1097Int { public: C1097Int(long long llData = 0) :m_iData(llData% MOD) {
} C1097Int operator+(const C1097Int& o)const { return C1097Int(((long long)m_iData + o.m_iData) % MOD); } C1097Int& operator+=(const C1097Int& o) { m_iData = ((long long)m_iData + o.m_iData) % MOD; return *this; } C1097Int& operator-=(const C1097Int& o) { m_iData = (m_iData + MOD - o.m_iData) % MOD; return *this; } C1097Int operator-(const C1097Int& o) { return C1097Int((m_iData + MOD - o.m_iData) % MOD); } C1097Int operator*(const C1097Int& o)const { return((long long)m_iData * o.m_iData) % MOD; } C1097Int& operator*=(const C1097Int& o) { m_iData = ((long long)m_iData * o.m_iData) % MOD; return *this; } bool operator<(const C1097Int& o)const { return m_iData < o.m_iData; } C1097Int pow(long long n)const { C1097Int iRet = 1, iCur = *this; while (n) { if (n & 1) { iRet *= iCur; } iCur *= iCur; n >>= 1; } return iRet; } C1097Int PowNegative1()const { return pow(MOD - 2); } int ToInt()const { return m_iData; }
private: int m_iData = 0;; }; template<class TSave, class TRecord, TRecord RecordNull = 0> class CLineTree { public: CLineTree(int iEleSize) :m_iEleSize(iEleSize), m_vArr(m_iEleSize * 4), m_vRecord(m_iEleSize * 4, RecordNull) {
} void Update(int iLeftIndex, int iRightIndex, TRecord value) { Update(1, 1, m_iEleSize, iLeftIndex + 1, iRightIndex + 1, value); } template<class TGet> void Query(const TGet& oGet, int iLeftIndex, int iRightIndex) { Query(oGet, 1, 1, m_iEleSize, iLeftIndex + 1, iRightIndex + 1); }
private: virtual void OnUpdateRecord(TRecord& old, const TRecord& newRecord) = 0; virtual void OnUpdateParent(TSave& par, const TSave& left, const TSave& r) = 0; virtual void OnUpdate(TSave& save, const int& len, const TRecord& iUpdate) = 0; template void Query(const TGet& oGet, int iNode, int iSaveLeft, int iSaveRight, int iQueryLeft, int iQueryRight) { if ((iQueryLeft <= iSaveLeft) && (iQueryRight >= iSaveRight)) { oGet(m_vArr[iNode]); return; } Fresh(iNode, iSaveLeft, iSaveRight); const int iMid = iSaveLeft + (iSaveRight - iSaveLeft) / 2; if (iMid >= iQueryLeft) { Query(oGet, iNode * 2, iSaveLeft, iMid, iQueryLeft, iQueryRight); } if (iMid + 1 <= iQueryRight) { Query(oGet, iNode * 2 + 1, iMid + 1, iSaveRight, iQueryLeft, iQueryRight); } } void Update(int iNode, int iSaveLeft, int iSaveRight, int iOpeLeft, int iOpeRight, TRecord value) { if (iNode >= m_vArr.size()) { return; } if ((iOpeLeft <= iSaveLeft) && (iOpeRight >= iSaveRight)) { OnUpdate(m_vArr[iNode], min(iSaveRight, iOpeRight) - max(iSaveLeft, iOpeLeft) + 1, value); OnUpdateRecord(m_vRecord[iNode], value); return; } Fresh(iNode, iSaveLeft, iSaveRight); const int iMid = iSaveLeft + (iSaveRight - iSaveLeft) / 2; if (iMid >= iOpeLeft) { Update(iNode * 2, iSaveLeft, iMid, iOpeLeft, iOpeRight, value); } if (iMid + 1 <= iOpeRight) { Update(iNode * 2 + 1, iMid + 1, iSaveRight, iOpeLeft, iOpeRight, value); } // 如果有后代,至少两个后代 OnUpdateParent(m_vArr[iNode], m_vArr[iNode * 2], m_vArr[iNode * 2 + 1]); } void Fresh(int iNode, int iDataLeft, int iDataRight) { if (RecordNull == m_vRecord[iNode]) { return; } const int iMid = iDataLeft + (iDataRight - iDataLeft) / 2; Update(iNode * 2, iDataLeft, iMid, iDataLeft, iMid, m_vRecord[iNode]); Update(iNode * 2 + 1, iMid + 1, iDataRight, iMid + 1, iDataRight, m_vRecord[iNode]); m_vRecord[iNode] = RecordNull; } const int m_iEleSize; vector m_vArr; vector m_vRecord; }; const long long llUnit = 2000’000’000; template<class TSave = C1097Int<>, class TRecord = long long, TRecord RecordNull = llUnit > class CMyLineTree : public CLineTree<TSave, TRecord, RecordNull> { public: using CLineTree<TSave, TRecord, RecordNull>::CLineTree; protected: virtual void OnUpdateRecord(TRecord& old, const TRecord& newRecord) override { long long mul = (old/ llUnit) * (newRecord/ llUnit); long long add = (old% llUnit) * (newRecord/ llUnit) + (newRecord% llUnit); old = C1097Int<>(mul).ToInt()*llUnit + C1097Int<>(add).ToInt(); } virtual void OnUpdateParent(TSave& par, const TSave& left, const TSave& r) override { } virtual void OnUpdate(TSave& save, const int& len, const TRecord& iUpdate) override { save = save * (iUpdate/ llUnit) + iUpdate% llUnit ; } }; class Fancy { public: Fancy():m_lineTree(100’000){ } void append(int val) { m_lineTree.Update(m_iSize, m_iSize, llUnit + val ); m_iSize++; } void addAll(int inc) { m_lineTree.Update(0, m_iSize-1, llUnit + inc); } void multAll(int m) { m_lineTree.Update(0, m_iSize - 1, llUnit *m); } int getIndex(int idx) { if (idx >= m_iSize) { return -1; } C1097Int<> iiRet = 0; auto Get = [&](const C1097Int<>& value ) { iiRet += value; }; m_lineTree.Query(Get,idx,idx); return iiRet.ToInt(); } CMyLineTree<> m_lineTree; int m_iSize=0; };
扩展阅读
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测试环境
操作系统:win7 开发环境: VS2019 C++17
或者 操作系统:win10 开发环境: VS2022 C++17
如无特殊说明,本算法用**C++**实现。