mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-11-23 22:08:47 +00:00
134 lines
2.7 KiB
C++
134 lines
2.7 KiB
C++
#include <iostream>
|
|
#include <cstring>
|
|
#include <queue>
|
|
|
|
using std::cin;
|
|
using std::cout;
|
|
const char endl = '\n';
|
|
|
|
const int N = 5005,
|
|
M = 100005,
|
|
INF = 0x3f3f3f3f;
|
|
|
|
int n, k, s, t, ans;
|
|
|
|
// Graph
|
|
int idx, head[N], ver[M << 1], next[M << 1];
|
|
std::pair<int, int> edge[M << 1];
|
|
|
|
// <flow, cost>
|
|
|
|
void add(int u, int v, int flow, int cost) {
|
|
next[idx] = head[u];
|
|
ver[idx] = v;
|
|
edge[idx] = std::make_pair(flow, cost);
|
|
head[u] = idx++;
|
|
}
|
|
|
|
inline int id(int i, int j, int k = 0) {
|
|
return (i - 1) * n + j + k * n * n;
|
|
}
|
|
|
|
// Dinic
|
|
int dist[N];
|
|
bool vis[N];
|
|
|
|
bool spfa() {
|
|
memset(vis, 0x00, sizeof(vis));
|
|
memset(dist, 0x3f, sizeof(dist));
|
|
|
|
std::queue<int> q;
|
|
q.push(s);
|
|
dist[s] = 0;
|
|
vis[s] = true;
|
|
|
|
while (!q.empty()) {
|
|
int u = q.front();
|
|
q.pop();
|
|
vis[u] = false;
|
|
|
|
for (int i = head[u]; ~i; i = next[i]) {
|
|
int v = ver[i],
|
|
c = edge[i].first,
|
|
w = edge[i].second;
|
|
|
|
if (c > 0 && dist[v] > dist[u] + w) {
|
|
dist[v] = dist[u] + w;
|
|
if (!vis[v]) {
|
|
q.push(v);
|
|
vis[v] = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return dist[t] != INF;
|
|
}
|
|
|
|
int dinic(int u, int limit) {
|
|
if (u == t) return limit;
|
|
|
|
int flow = 0;
|
|
vis[u] = true;
|
|
for (int i = head[u]; ~i && flow < limit; i = next[i]) {
|
|
int v = ver[i],
|
|
c = edge[i].first,
|
|
w = edge[i].second;
|
|
if (dist[v] == dist[u] + w && c && !vis[v]) {
|
|
int k = dinic(v, std::min(c, limit - flow));
|
|
if (!k) dist[v] = INF;
|
|
edge[i].first -= k;
|
|
edge[i ^ 1].first += k;
|
|
flow += k;
|
|
ans += k * w;
|
|
}
|
|
}
|
|
vis[u] = false;
|
|
|
|
return flow;
|
|
}
|
|
|
|
int main() {
|
|
std::ios::sync_with_stdio(false);
|
|
|
|
memset(head, 0xff, sizeof(head));
|
|
|
|
cin >> n >> k;
|
|
|
|
s = 0;
|
|
add(s, id(1, 1), k, 0);
|
|
add(id(1, 1), s, 0, 0);
|
|
|
|
t = id(n, n, 1) + 1;
|
|
add(id(n, n, 1), t, k, 0);
|
|
add(t, id(n, n, 1), 0, 0);
|
|
|
|
for (int i = 1; i <= n; i++) {
|
|
for (int j = 1; j <= n; j++) {
|
|
int w;
|
|
cin >> w;
|
|
|
|
add(id(i, j), id(i, j, 1), 1, -w);
|
|
add(id(i, j, 1), id(i, j), 0, w);
|
|
|
|
add(id(i, j), id(i, j, 1), INF, 0);
|
|
add(id(i, j, 1), id(i, j), 0, 0);
|
|
|
|
if (i < n) {
|
|
add(id(i, j, 1), id(i + 1, j), INF, 0);
|
|
add(id(i + 1, j), id(i, j, 1), 0, 0);
|
|
}
|
|
|
|
if (j < n) {
|
|
add(id(i, j, 1), id(i, j + 1), INF, 0);
|
|
add(id(i, j + 1), id(i, j, 1), 0, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
while (spfa()) dinic(s, INF);
|
|
|
|
cout << -ans << endl;
|
|
return 0;
|
|
}
|