1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
// Laufzeit: O(n^2)
vector<vector<double>> dist; // Initialisiere mit Entfernungen zwischen Punkten.
vector<vector<double>> dp;
vector<vector<bool>> choice;
double get(int p1, int p2) {
int v = max(p1, p2) + 1;
if (v == dist.size()) return dist[p1][v - 1] + dist[p2][v - 1];
if (dp[p1][p2] >= 0.0) return dp[p1][p2];
double tryLR = dist[p1][v] + get(v, p2), tryRL = dist[p2][v] + get(p1, v);
choice[p1][p2] = tryLR < tryRL;
return dp[p1][p2] = min(tryLR, tryRL);
}
void bitonicTour() {
dp = vector<vector<double>>(dist.size(), vector<double>(dist.size(), -1));
choice = vector<vector<bool>>(dist.size(), vector<bool>(dist.size()));
get(0, 0);
// return dp[0][0]; // Länger der Tour
vector<int> lr = {0}, rl = {0};
for (int p1 = 0, p2 = 0, v; (v = max(p1, p2) + 1) < dist.size();) {
if (choice[p1][p2]) {
lr.push_back(v); p1 = v;
} else {
rl.push_back(v); p2 = v;
}}
lr.insert(lr.end(), rl.rbegin(), rl.rend());
// return lr; // Enthält Knoten 0 zweimal. An erster und letzter Position.
}
|
