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各个根节点保存的该集合的数量。叶子节点保存的根节点的下标。代码实现如下
UnionFindSet.h
#pragma once
#include <vector>
#include <map>//template<class T>
//class UnionFindSet
//{
//public:
// UnionFindSet(const T* a, size_t n)
// {
// for (size_t i = 0; i < n; ++i)
// {
// _a.push_back(a[i]);
// _indexMap[a[i]] = i;
// }
// }
//private:
// vector<T> _a; // 编号找人
// map<T, int> _indexMap; // 人找编号
//};class UnionFindSet
{
public:UnionFindSet(size_t n):_ufs(n, -1){}void Union(int x1, int x2){int root1 = FindRoot(x1);int root2 = FindRoot(x2);// 如果本身就在一个集合就没必要合并了if (root1 == root2)return;// 控制数据量小的往大的集合合并if (abs(_ufs[root1]) < abs(_ufs[root2]))swap(root1, root2);_ufs[root1] += _ufs[root2];_ufs[root2] = root1;}int FindRoot(int x){int root = x;while (_ufs[root] >= 0){root = _ufs[root];}// 路径压缩while (_ufs[x] >= 0){int parent = _ufs[x];_ufs[x] = root;x = parent;}return root;}bool InSet(int x1, int x2){return FindRoot(x1) == FindRoot(x2);}size_t SetSize(){size_t size = 0;for (size_t i = 0; i < _ufs.size(); ++i){if (_ufs[i] < 0){++size;}}return size;}private:vector<int> _ufs;
};void TestUnionFindSet()
{UnionFindSet ufs(10);ufs.Union(8, 9);ufs.Union(7, 8);ufs.Union(6, 7);ufs.Union(5, 6);ufs.Union(4, 5);ufs.FindRoot(6);ufs.FindRoot(9);
}
Graph.h
#pragma once
#include <vector>
#include <map>
#include <set>
#include <string>
#include <queue>
#include <functional>// weight
namespace matrix
{template<class V, class W, W MAX_W = INT_MAX, bool Direction = false>class Graph{typedef Graph<V, W, MAX_W, Direction> Self;public:Graph() = default;// 图的创建// 1、IO输入 -- 不方便测试,oj中更适合// 2、图结构关系写到文件,读取文件// 3、手动添加边Graph(const V* a, size_t n){_vertexs.reserve(n);for (size_t i = 0; i < n; ++i){_vertexs.push_back(a[i]);_indexMap[a[i]] = i;}_matrix.resize(n);for (size_t i = 0; i < _matrix.size(); ++i){_matrix[i].resize(n, MAX_W);}}size_t GetVertexIndex(const V& v){auto it = _indexMap.find(v);if (it != _indexMap.end()){return it->second;}else{//assert(false);cout << "不存在顶点" << ":" << v << endl;throw invalid_argument("顶点不存在");return -1;}}void _AddEdge(size_t srci, size_t dsti, const W& w){_matrix[srci][dsti] = w;// 无向图if (Direction == false){_matrix[dsti][srci] = w;}}void AddEdge(const V& src, const V& dst, const W& w){size_t srci = GetVertexIndex(src);size_t dsti = GetVertexIndex(dst);_AddEdge(srci, dsti, w);}void Print(){// 顶点for (size_t i = 0; i < _vertexs.size(); ++i){cout << "[" << i << "]" << "->" << _vertexs[i] << endl;}cout << endl;// 矩阵// 横下标cout << " ";for (size_t i = 0; i < _vertexs.size(); ++i){//cout << i << " ";printf("%4d", i);}cout << endl;for (size_t i = 0; i < _matrix.size(); ++i){cout << i << " "; // 竖下标for (size_t j = 0; j < _matrix[i].size(); ++j){//cout << _matrix[i][j] << " ";if (_matrix[i][j] == MAX_W){//cout << "* ";printf("%4c", '*');}else{//cout << _matrix[i][j] << " ";printf("%4d", _matrix[i][j]);}}cout << endl;}cout << endl;for (size_t i = 0; i < _matrix.size(); ++i){for (size_t j = 0; j < _matrix[i].size(); ++j){if (i < j && _matrix[i][j] != MAX_W){cout << _vertexs[i] << "->" << _vertexs[j] << ":" << _matrix[i][j] << endl;}}}}//void BFS(const V& src)//{// size_t srci = GetVertexIndex(src);// // 队列和标记数组// queue<int> q;// vector<bool> visited(_vertexs.size(), false);// q.push(srci);// visited[srci] = true;// size_t n = _vertexs.size();// while (!q.empty())// {// int front = q.front();// q.pop();// cout << front <<":"<<_vertexs[front] << endl;// // 把front顶点的邻接顶点入队列// for (size_t i = 0; i < n; ++i)// {// if (_matrix[front][i] != MAX_W)// {// if (visited[i] == false)// {// q.push(i);// visited[i] = true;// }// }// }// }// cout << endl;//}void BFS(const V& src){size_t srci = GetVertexIndex(src);// 队列和标记数组queue<int> q;vector<bool> visited(_vertexs.size(), false);q.push(srci);visited[srci] = true;int levelSize = 1;size_t n = _vertexs.size();while (!q.empty()){// 一层一层出for (int i = 0; i < levelSize; ++i){int front = q.front();q.pop();cout << front << ":" << _vertexs[front] << " ";// 把front顶点的邻接顶点入队列for (size_t i = 0; i < n; ++i){if (_matrix[front][i] != MAX_W){if (visited[i] == false){q.push(i);visited[i] = true;}}}}cout << endl;levelSize = q.size();}cout << endl;}void _DFS(size_t srci, vector<bool>& visited){cout << srci << ":" << _vertexs[srci] << endl;visited[srci] = true;// 找一个srci相邻的没有访问过的点,去往深度遍历for (size_t i = 0; i < _vertexs.size(); ++i){if (_matrix[srci][i] != MAX_W && visited[i] == false){_DFS(i, visited);}}}void DFS(const V& src){size_t srci = GetVertexIndex(src);vector<bool> visited(_vertexs.size(), false);_DFS(srci, visited);}struct Edge{size_t _srci;size_t _dsti;W _w;Edge(size_t srci, size_t dsti, const W& w):_srci(srci), _dsti(dsti), _w(w){}bool operator>(const Edge& e) const{return _w > e._w;}};W Kruskal(Self& minTree){size_t n = _vertexs.size();minTree._vertexs = _vertexs;minTree._indexMap = _indexMap;minTree._matrix.resize(n);for (size_t i = 0; i < n; ++i){minTree._matrix[i].resize(n, MAX_W);}priority_queue<Edge, vector<Edge>, greater<Edge>> minque;for (size_t i = 0; i < n; ++i){for (size_t j = 0; j < n; ++j){if (i < j && _matrix[i][j] != MAX_W){minque.push(Edge(i, j, _matrix[i][j]));}}}// 选出n-1条边int size = 0;W totalW = W();UnionFindSet ufs(n);while (!minque.empty()){Edge min = minque.top();minque.pop();if (!ufs.InSet(min._srci, min._dsti)){//cout << _vertexs[min._srci] << "->" << _vertexs[min._dsti] <<":"<<min._w << endl;minTree._AddEdge(min._srci, min._dsti, min._w);ufs.Union(min._srci, min._dsti);++size;totalW += min._w;}else{//cout << "构成环:";//cout << _vertexs[min._srci] << "->" << _vertexs[min._dsti] << ":" << min._w << endl;}}if (size == n - 1){return totalW;}else{return W();}}W Prim(Self& minTree, const W& src){size_t srci = GetVertexIndex(src);size_t n = _vertexs.size();minTree._vertexs = _vertexs;minTree._indexMap = _indexMap;minTree._matrix.resize(n);for (size_t i = 0; i < n; ++i){minTree._matrix[i].resize(n, MAX_W);}/*set<int> X;set<int> Y;X.insert(srci);for (size_t i = 0; i < n; ++i){if (i != srci){Y.insert(i);}}*/vector<bool> X(n, false);vector<bool> Y(n, true);X[srci] = true;Y[srci] = false;// 从X->Y集合中连接的边里面选出最小的边priority_queue<Edge, vector<Edge>, greater<Edge>> minq;// 先把srci连接的边添加到队列中for (size_t i = 0; i < n; ++i){if (_matrix[srci][i] != MAX_W){minq.push(Edge(srci, i, _matrix[srci][i]));}}cout << "Prim开始选边" << endl;size_t size = 0;W totalW = W();while (!minq.empty()){Edge min = minq.top();minq.pop();// 最小边的目标点也在X集合,则构成环if (X[min._dsti]){//cout << "构成环:";//cout << _vertexs[min._srci] << "->" << _vertexs[min._dsti] << ":" << min._w << endl;}else{minTree._AddEdge(min._srci, min._dsti, min._w);//cout << _vertexs[min._srci] << "->" << _vertexs[min._dsti] << ":" << min._w << endl;X[min._dsti] = true;Y[min._dsti] = false;++size;totalW += min._w;if (size == n - 1)break;for (size_t i = 0; i < n; ++i){if (_matrix[min._dsti][i] != MAX_W && Y[i]){minq.push(Edge(min._dsti, i, _matrix[min._dsti][i]));}}}}if (size == n - 1){return totalW;}else{return W();}}void PrintShortPath(const V& src, const vector<W>& dist, const vector<int>& pPath){size_t srci = GetVertexIndex(src);size_t n = _vertexs.size();for (size_t i = 0; i < n; ++i){if (i != srci){// 找出i顶点的路径vector<int> path;size_t parenti = i;while (parenti != srci){path.push_back(parenti);parenti = pPath[parenti];}path.push_back(srci);reverse(path.begin(), path.end());for (auto index : path){cout << _vertexs[index] << "->";}cout << dist[i] << endl;}}}void Dijkstra(const V& src, vector<W>& dist, vector<int>& pPath){size_t srci = GetVertexIndex(src);size_t n = _vertexs.size();dist.resize(n, MAX_W);pPath.resize(n, -1);dist[srci] = 0;pPath[srci] = srci;// 已经确定最短路径的顶点集合vector<bool> S(n, false);for (size_t j = 0; j < n; ++j){// 选最短路径顶点且不在S更新其他路径int u = 0;W min = MAX_W;for (size_t i = 0; i < n; ++i){if (S[i] == false && dist[i] < min){u = i;min = dist[i];}}S[u] = true;// 松弛更新u连接顶点v srci->u + u->v < srci->v 更新for (size_t v = 0; v < n; ++v){if (S[v] == false && _matrix[u][v] != MAX_W&& dist[u] + _matrix[u][v] < dist[v]){dist[v] = dist[u] + _matrix[u][v];pPath[v] = u;}}}}private:vector<V> _vertexs; // 顶点集合map<V, int> _indexMap; // 顶点映射下标vector<vector<W>> _matrix; // 邻接矩阵};void TestGraph1(){Graph<char, int, INT_MAX, true> g("0123", 4);g.AddEdge('0', '1', 1);g.AddEdge('0', '3', 4);g.AddEdge('1', '3', 2);g.AddEdge('1', '2', 9);g.AddEdge('2', '3', 8);g.AddEdge('2', '1', 5);g.AddEdge('2', '0', 3);g.AddEdge('3', '2', 6);g.Print();}void TestBDFS(){string a[] = { "张三", "李四", "王五", "赵六", "周七" };Graph<string, int> g1(a, sizeof(a) / sizeof(string));g1.AddEdge("张三", "李四", 100);g1.AddEdge("张三", "王五", 200);g1.AddEdge("王五", "赵六", 30);g1.AddEdge("王五", "周七", 30);g1.Print();g1.BFS("张三");g1.DFS("张三");}void TestGraphMinTree(){const char str[] = "abcdefghi";Graph<char, int> g(str, strlen(str));g.AddEdge('a', 'b', 4);g.AddEdge('a', 'h', 8);//g.AddEdge('a', 'h', 9);g.AddEdge('b', 'c', 8);g.AddEdge('b', 'h', 11);g.AddEdge('c', 'i', 2);g.AddEdge('c', 'f', 4);g.AddEdge('c', 'd', 7);g.AddEdge('d', 'f', 14);g.AddEdge('d', 'e', 9);g.AddEdge('e', 'f', 10);g.AddEdge('f', 'g', 2);g.AddEdge('g', 'h', 1);g.AddEdge('g', 'i', 6);g.AddEdge('h', 'i', 7);Graph<char, int> kminTree;cout << "Kruskal:" << g.Kruskal(kminTree) << endl;kminTree.Print();cout << endl << endl;Graph<char, int> pminTree;cout << "Prim:" << g.Prim(pminTree, 'a') << endl;pminTree.Print();cout << endl;for (size_t i = 0; i < strlen(str); ++i){cout << "Prim:" << g.Prim(pminTree, str[i]) << endl;}}void TestGraphDijkstra(){/*const char* str = "syztx";Graph<char, int, INT_MAX, true> g(str, strlen(str));g.AddEdge('s', 't', 10);g.AddEdge('s', 'y', 5);g.AddEdge('y', 't', 3);g.AddEdge('y', 'x', 9);g.AddEdge('y', 'z', 2);g.AddEdge('z', 's', 7);g.AddEdge('z', 'x', 6);g.AddEdge('t', 'y', 2);g.AddEdge('t', 'x', 1);g.AddEdge('x', 'z', 4);vector<int> dist;vector<int> parentPath;g.Dijkstra('s', dist, parentPath);g.PrintShortPath('s', dist, parentPath);*/// 图中带有负权路径时,贪心策略则失效了。// 测试结果可以看到s->t->y之间的最短路径没更新出来const char* str = "sytx";Graph<char, int, INT_MAX, true> g(str, strlen(str));g.AddEdge('s', 't', 10);g.AddEdge('s', 'y', 5);g.AddEdge('t', 'y', -7);g.AddEdge('y', 'x', 3);vector<int> dist;vector<int> parentPath;g.Dijkstra('s', dist, parentPath);g.PrintShortPath('s', dist, parentPath);}
}namespace link_table
{template<class W>struct Edge{//int _srci;int _dsti; // 目标点的下标W _w; // 权值Edge<W>* _next;Edge(int dsti, const W& w):_dsti(dsti), _w(w), _next(nullptr){}};template<class V, class W, bool Direction = false>class Graph{typedef Edge<W> Edge;public:Graph(const V* a, size_t n){_vertexs.reserve(n);for (size_t i = 0; i < n; ++i){_vertexs.push_back(a[i]);_indexMap[a[i]] = i;}_tables.resize(n, nullptr);}size_t GetVertexIndex(const V& v){auto it = _indexMap.find(v);if (it != _indexMap.end()){return it->second;}else{//assert(false);throw invalid_argument("顶点不存在");return -1;}}void AddEdge(const V& src, const V& dst, const W& w){size_t srci = GetVertexIndex(src);size_t dsti = GetVertexIndex(dst);// 1->2Edge* eg = new Edge(dsti, w);eg->_next = _tables[srci];_tables[srci] = eg;// 2->1if (Direction == false){Edge* eg = new Edge(srci, w);eg->_next = _tables[dsti];_tables[dsti] = eg;}}void Print(){// 顶点for (size_t i = 0; i < _vertexs.size(); ++i){cout << "[" << i << "]" << "->" << _vertexs[i] << endl;}cout << endl;for (size_t i = 0; i < _tables.size(); ++i){cout << _vertexs[i] << "[" << i << "]->";Edge* cur = _tables[i];while (cur){cout << "[" << _vertexs[cur->_dsti] << ":" << cur->_dsti << ":" << cur->_w << "]->";cur = cur->_next;}cout << "nullptr" << endl;}}private:vector<V> _vertexs; // 顶点集合map<V, int> _indexMap; // 顶点映射下标vector<Edge*> _tables; // 邻接表};void TestGraph1(){/*Graph<char, int, true> g("0123", 4);g.AddEdge('0', '1', 1);g.AddEdge('0', '3', 4);g.AddEdge('1', '3', 2);g.AddEdge('1', '2', 9);g.AddEdge('2', '3', 8);g.AddEdge('2', '1', 5);g.AddEdge('2', '0', 3);g.AddEdge('3', '2', 6);g.Print();*/string a[] = { "张三", "李四", "王五", "赵六" };Graph<string, int, true> g1(a, 4);g1.AddEdge("张三", "李四", 100);g1.AddEdge("张三", "王五", 200);g1.AddEdge("王五", "赵六", 30);g1.Print();}
}
Test.cpp
#include <iostream>
using namespace std;#include "UnionFindSet.h"
#include"Graph.h"//int main()
//{
// string a[] = { "", "", "", "" };
// UnionFindSet<string> ufs(a, 4);
//
// return 0;
//}int main()
{//matrix::TestGraph1();//matrix::TestBDFS();//matrix::TestGraphMinTree();matrix::TestGraphDijkstra();//link_table::TestGraph1();//TestUnionFindSet();return 0;
}
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