| author | beckerjc |
| Wed, 03 Mar 2004 19:16:48 +0000 | |
| changeset 150 | 4b5210aa0239 |
| child 218 | 5964f1c64ca1 |
| permissions | -rw-r--r-- |
| beckerjc@150 | 1 |
// -*- c++ -*- // |
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#ifndef UNION_FIND_H |
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#define UNION_FIND_H |
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#include <vector> |
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#include <utility> |
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namespace hugo {
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template <typename T, typename TIntMap> |
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class UnionFind {
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public: |
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typedef T ElementType; |
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typedef std::pair<int,int> PairType; |
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private: |
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std::vector<PairType> data; |
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TIntMap& map; |
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public: |
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UnionFind(TIntMap& m) : map(m) {}
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int whichComponent(T a) |
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{
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int comp0 = map.get(a); |
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if (comp0 < 0) {
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return insertNewElement(a); |
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} |
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int comp = comp0; |
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int next; |
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while ( (next = data[comp].first) != comp) {
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comp = next; |
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} |
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while ( (next = data[comp0].first) != comp) {
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data[comp0].first = comp; |
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comp0 = next; |
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} |
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return comp; |
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} |
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int insertNewElement(T a) |
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{
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int n = data.size(); |
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data.push_back(make_pair(n, 1)); |
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map.set(a,n); |
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return n; |
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} |
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bool joinComponents(T a, T b) |
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{
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int ca = whichComponent(a); |
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int cb = whichComponent(b); |
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if ( ca == cb ) |
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return false; |
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if ( data[ca].second > data[cb].second ) {
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data[cb].first = ca; |
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data[ca].second += data[cb].second; |
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} |
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else {
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data[ca].first = cb; |
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data[cb].second += data[ca].second; |
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} |
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return true; |
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} |
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}; |
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} //namespace hugo |
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#endif //UNION_FIND_H |