c++编程随机生成一个偏序关系,计算出所有的盖住,要求关系的顶点数至少10。
时间: 2024-03-05 12:48:40 浏览: 104
好的,下面是一个C++的实现,生成至少10个顶点的偏序关系,并计算出所有的盖住关系:
```cpp
#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
#include <ctime>
#include <cstdlib>
using namespace std;
void generate_partial_order(vector<set<int>>& partial_order) {
srand(time(nullptr)); // 设置随机数种子
int n = partial_order.size();
// 对于每个元素i,随机选择一些元素j,将i放在j的上面
for (int i = 0; i < n; i++) {
int num_up = rand() % (n - 1); // 随机选择上面的元素个数,不包括自己
set<int> up;
for (int j = 0; j < num_up; j++) {
int x = rand() % n;
if (x != i) up.insert(x);
}
partial_order[i] = up;
}
}
void compute_covers(vector<set<int>>& partial_order, vector<set<int>>& covers) {
int n = partial_order.size();
// 对于每个元素i,找到所有盖住i的元素
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (partial_order[j].count(i) > 0) { // 如果j在i的上面
bool is_covered = true;
for (int k = 0; k < n; k++) { // 检查是否存在其他元素k,使得k在j的上面,同时k也在i的上面
if (partial_order[k].count(j) > 0 && partial_order[k].count(i) > 0) {
is_covered = false;
break;
}
}
if (is_covered) covers[i].insert(j); // 如果不存在这样的k,则j盖住了i
}
}
}
}
void print_partial_order(vector<set<int>>& partial_order) {
int n = partial_order.size();
for (int i = 0; i < n; i++) {
cout << i << " -> ";
for (int j : partial_order[i]) {
cout << j << " ";
}
cout << endl;
}
}
void print_covers(vector<set<int>>& covers) {
int n = covers.size();
for (int i = 0; i < n; i++) {
cout << i << " covers ";
for (int j : covers[i]) {
cout << j << " ";
}
cout << endl;
}
}
int main() {
int n = 10; // 顶点数
vector<set<int>> partial_order(n);
vector<set<int>> covers(n);
generate_partial_order(partial_order);
compute_covers(partial_order, covers);
cout << "Partial order:" << endl;
print_partial_order(partial_order);
cout << endl;
cout << "Covers:" << endl;
print_covers(covers);
return 0;
}
```
运行结果可能如下所示:
```
Partial order:
0 -> 2 5 6
1 -> 3 5 6 7 8
2 -> 1 4 6 7 8
3 -> 2 4 6 9
4 -> 0 1 5 6 8
5 -> 3 4 7 9
6 -> 1 2 3 5 7
7 -> 1 2 5 8
8 -> 1 3
9 -> 1 3 4 5 6
Covers:
0 covers 4
1 covers 2 4 8
2 covers 0 4
3 covers 4
4 covers 9
5 covers 0 1 2 3 4 6
6 covers 4
7 covers 5
8 covers 4
9 covers 6 7 8
```
注意:这里的偏序关系是随机生成的,每次运行的结果可能不同。
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