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| #include <iostream>
#include <vector>
#include <unordered_map>
#include <unordered_set>
#include <set>
#include <algorithm>
#include <climits>
#include <stack>
#include <queue>
#include <map>
#include <iterator>
#include <assert.h>
using namespace std;
struct Node {
int rank;
int value;
Node * parent;
};
class DisjointSets{
private:
int _count;
int _numElements;
int _numSets;
unordered_map<int, Node *> _nodes;
public:
DisjointSets(): _numElements(0), _numSets(0){}
~DisjointSets(){
for(auto it = _nodes.begin(); it != _nodes.end(); ++it){
delete it->second;
}
_nodes.clear();
}
int find_set(int element) {
if(!_nodes.count(element)){
return -1;
}
Node * curr = _nodes[element];
while(curr->parent){
curr = curr->parent;
}
Node * root = curr;
// update the parents along the way
curr = _nodes[element];
while(curr != root){
Node * next = curr->parent;
curr->parent = root;
curr = next;
}
return root->value;
}
void make_union(int setId1, int setId2){
if(setId1 == setId2){
return;
}
if(!_nodes.count(setId1)){
return;
}
Node* set1 = _nodes[setId1];
if(!_nodes.count(setId2)){
return;
}
Node* set2 = _nodes[setId2];
if(set1->rank > set2->rank){
set2->parent = set1;
} else if(set1->rank < set2->rank){
set1->parent = set2;
} else {
set2->parent = set1;
set1->rank++;
}
--_numSets;
}
void add_element(int element) {
_nodes[element] = new Node();
_nodes[element]->parent = NULL;
_nodes[element]->value = element;
_nodes[element]->rank = 0;
_numElements++;;
_numSets++;
}
int get_num_elements() const {
return _numElements;
}
int get_num_sets() const {
return _numSets;
}
};
void printElementSets(DisjointSets & s, const vector<int>& nums)
{
assert(nums.size() <= s.get_num_elements());
for (int i = 0; i < nums.size(); ++i) {
cout << s.find_set(nums[i]) << " ";
}
cout << endl;
}
void groupTogether(DisjointSets& s, const vector<int>& nums, map<int, vector<int>>& groups){
assert(nums.size() <= s.get_num_elements());
for (int i = 0; i < nums.size() && i < s.get_num_elements(); ++i) {
groups[s.find_set(nums[i])].push_back(nums[i]);
}
}
void prettyPrintGroups(const map<int, vector<int>>& groups){
for(auto it = groups.begin(); it != groups.end(); ++it){
std::cout << "Group " << it->first << " -------------"<< std::endl;
for(int i = 0; i < it->second.size(); ++i){
std::cout << it->second[i] << " ";
}
std::cout << std::endl;
}
}
void testGenerator(int size){
vector<pair<int, int>> rules{{0, 0}, {1, 5}, {10, 30}, {30, 60}, {60, 100}};
vector<int> randoms;
for(int i = 0; i < size; ++i){
randoms.push_back(random() % 100);
}
DisjointSets s;
for_each(randoms.begin(), randoms.end(), [&](int num){s.add_element(num); });
std::cout << "Orginal data:" << std::endl;
printElementSets(s, randoms);
for(int i = 0; i < rules.size(); ++i){
int rep = rules[i].first;
// push representative to DisjointSets
s.add_element(rep);
for(int j = rules[i].first + 1 ; j < rules[i].second; ++j){
s.make_union(s.find_set(rep), s.find_set(j));
}
}
std::cout << "After union find, group representative:" << std::endl;
printElementSets(s, randoms);
std::cout << std::endl;
// group together
map<int, vector<int>> groups;
groupTogether(s, randoms, groups);
prettyPrintGroups(groups);
}
int main(int argc, char *argv[])
{
const int DATA_SIZE = 10;
testGenerator(DATA_SIZE);
return 0;
}
|