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
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
| #include <bits/stdc++.h>
#define R register
#define ll long long
#define cmin(a, b) ((a < b) ? a : b)
#define cmax(a, b) ((a < b) ? b : a)
const double delta = 0.999;
const int MaxN = 20;
int n, ans = 0x3f3f3f3f;
double t = 10000000.0;
int pos[MaxN], fri[MaxN][4], g[MaxN][MaxN];
inline int read()
{
int x = 0;
char ch = getchar();
while (ch > '9' || ch < '0')
ch = getchar();
while (ch <= '9' && ch >= '0')
x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
return x;
}
inline int calc()
{
int ret = 0;
for (int i = 1; i <= n; i++)
{
ret += abs(pos[i] - pos[fri[i][1]]);
ret += abs(pos[i] - pos[fri[i][2]]);
ret += abs(pos[i] - pos[fri[i][3]]);
}
return ret / 2;
}
inline void SA()
{
t = 1.0;
while (t > 1e-10)
{
int x = rand() % n + 1, y = rand() % n + 1;
std::swap(pos[x], pos[y]);
int tmp = calc();
int del = tmp - ans;
if (del < 0)
ans = tmp;
else if (exp(-del / t) * RAND_MAX <= rand())
std::swap(pos[x], pos[y]);
t *= delta;
}
}
int main()
{
n = read();
srand(time(NULL));
for (int i = 1; i <= n; i++)
{
pos[i] = i;
for (int j = 1; j <= 3; j++)
fri[i][j] = read(), g[i][fri[i][j]] = 1, g[fri[i][j]][i] = 1;
}
for (int i = 1; i <= 100; i++)
SA();
printf("%d\n", ans);
return 0;
}
|