85 lines
2.2 KiB
C++
85 lines
2.2 KiB
C++
// vim: set ts=2 sw=2 et tw=80:
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#include "opt.h"
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using namespace std;
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typedef unsigned int uint;
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typedef tuple<uint, uint, uint> triple;
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ostream& operator<< (ostream& out, vector<uint> a) {
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out << "[";
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for (int i = 0; i < a.size() - 1; i++) {
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out << a[i] << ",";
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}
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out << a[a.size() - 1] << "]";
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return out;
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}
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ostream& operator<< (ostream& out, triple& a) {
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out << "(" << get<0>(a) << "," << get<1>(a) << "," << get<2>(a) << ")";
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return out;
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}
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double reverse_segment_if_better(vector<uint>& tour, const double (&dist_matrix) [1577][1577],
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uint i, uint j, uint k) {
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uint A = tour[i-1];
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uint B = tour[i];
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uint C = tour[j-1];
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uint D = tour[j];
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uint E = tour[k-1];
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uint F = tour[k % (tour.size()-1)];
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double d0 = (dist_matrix[A][B] + dist_matrix[C][D] + dist_matrix[E][F]);
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double d1 = (dist_matrix[A][C] + dist_matrix[B][D] + dist_matrix[E][F]);
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double d2 = (dist_matrix[A][B] + dist_matrix[C][E] + dist_matrix[D][F]);
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double d3 = (dist_matrix[A][D] + dist_matrix[E][B] + dist_matrix[C][F]);
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double d4 = (dist_matrix[F][B] + dist_matrix[C][D] + dist_matrix[E][A]);
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if (d0 > d1) {
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reverse(tour.begin() + i, tour.begin() + j);
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return -d0 + d1;
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}
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else if (d0 > d2) {
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reverse(tour.begin() + j, tour.begin() + k);
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return -d0 + d2;
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}
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else if (d0 > d4) {
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reverse(tour.begin() + i, tour.begin() + k);
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return -d0 + d4;
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}
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else if (d0 > d3) {
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vector<uint> tmp;
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for (uint z = j; z < k; z++) {
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tmp.push_back(tour[z]);
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}
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for (uint z = i; z < j; z++) {
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tmp.push_back(tour[z]);
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}
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for (uint f = i; f < k; f++) {
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tour[f] = tmp[f - i];
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}
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return -d0 + d3;
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}
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return 0;
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}
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void three_opt(vector<uint>& tour, const double (&dist_matrix) [1577][1577], double& sh_dist) {
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double delta = 0;
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uint n = tour.size() - 1;
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for (uint i = 0; i < 1; i++) {
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for (uint i = 1; i < n; i++)
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for (uint j = i+2; j < n; j++)
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for (uint k = j+2; k < n; k++) {
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double d = reverse_segment_if_better(tour, dist_matrix, i, j, k);
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if (d > 0) cerr << d << " " << i << "," << j << "," << k << endl;
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delta += d;
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}
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if (delta >= 0)
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break;
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}
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sh_dist += delta;
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}
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