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
63
64
65
66
67
68
69
70
71
|
#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
using ll = long long;
using ii = pair<int, int>;
const int dx[] = { 2, 1, -1, -2, -2, -1, 1, 2 };
const int dy[] = { 1, 2, 2, 1, -1, -2, -2, -1 };
int d[44][44];
bool b[44][44];
inline int & dist(int i, int j) { return d[i + 22][j + 22]; }
inline bool & vis(int i, int j) { return b[i + 22][j + 22]; }
ii P[202];
int dp[202][101];
int main() {
ios_base::sync_with_stdio(0), cin.tie(0);
int N, R, C;
cin >> N >> R >> C;
for (int i = 0; i < N; ++i) {
cin >> P[i].f >> P[i].s;
--P[i].f, --P[i].s;
}
// BFS to compute distances
auto valid = [&R, &C](int i, int j) { return i > -R && i < R && j > -C && j < C; };
dist(0, 0) = 0;
queue<ii> q;
q.emplace(0, 0);
while (q.size()) {
ii u = q.front();
q.pop();
if (vis(u.f, u.s)) continue;
vis(u.f, u.s) = 1;
for (int d = 0; d < 8; ++d) {
ii v(u.f + dx[d], u.s + dy[d]);
if (valid(v.f, v.s) && !vis(v.f, v.s)) {
dist(v.f, v.s) = dist(u.f, u.s) + 1;
q.push(v);
}
}
}
// O(R^2 * C^2 * N^2)
int ans = 1e9;
for (int a = 0; a < R; ++a) {
for (int b = 0; b < C; ++b) {
for (int c = a; c < R; ++c) {
for (int d = 0; d < C; ++d) {
if (a == c && b == d) continue;
// First meetup location: (a, b)
// Second meetup location: (c, d)
memset(dp, '?', sizeof dp);
dp[0][0] = 0;
for (int i = 0; i < N; ++i) {
for (int j = 0; j <= min(i, N / 2); ++j) {
dp[i + 1][j] = min(dist(P[i].f - a, P[i].s - b) + dp[i][j], dp[i + 1][j]);
dp[i + 1][j + 1] = min(dist(P[i].f - c, P[i].s - d) + dp[i][j], dp[i + 1][j + 1]);
}
}
ans = min(dp[N][N / 2], ans);
}
}
}
}
cout << ans << '\n';
}
|
