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| #include <bits/stdc++.h>
using namespace std;
inline int read() {
int x = 0; int f = 1; char ch = getchar();
while (!isdigit(ch)) {if (ch == '-') f = -1; ch = getchar();}
while (isdigit(ch)) {x = x * 10 + ch - 48; ch = getchar();}
return x * f;
}
const int maxn = 4010;
const int inf = 0x3f3f3f3f;
const int ninf = 0xc0c0c0c0;
int n, m, s, t, ansflow;
int vis[maxn], d[maxn], pre[maxn], a[maxn];
long long anscost;
struct Edge {
int from, to, cap, flow, cost;
Edge(int u, int v, int c, int f, int w): from(u), to(v), cap(c), flow(f), cost(w){}
};
vector<Edge> edges;
vector<int> G[maxn];
void add(int u, int v, int c, int w) {
edges.push_back(Edge(u, v, c, 0, w));
edges.push_back(Edge(v, u, 0, 0,-w));
int mm = edges.size();
G[u].push_back(mm - 2);
G[v].push_back(mm - 1);
}
bool BellmanFord(int& flow, long long& cost) {
memset(d, 0xc0, sizeof(d));
memset(vis, 0, sizeof(vis));
d[s] = 0; vis[s] = 1; pre[s] = 0; a[s] = inf;
queue<int> Q;
Q.push(s);
while (!Q.empty()) {
int x = Q.front(); Q.pop();
vis[x] = 0;
for (int i = 0; i < G[x].size(); ++i) {
Edge& e = edges[G[x][i]];
if (e.cap > e.flow && d[e.to] < d[x] + e.cost) {
d[e.to] = d[x] + e.cost;
pre[e.to] = G[x][i];
a[e.to] = min(a[x], e.cap - e.flow);
if (!vis[e.to]) {
Q.push(e.to);
vis[e.to] = 1;
}
}
}
}
if (d[t] == ninf) return false;
flow += a[t];
cost += (long long)d[t] * (long long)a[t];
for (int u = t; u != s; u = edges[pre[u]].from) {
edges[pre[u]].flow += a[t];
edges[pre[u] ^ 1].flow -= a[t];
}
return true;
}
int MaxCostMaxFlow(long long& cost) {
int flow = 0; cost = 0;
while (BellmanFord(flow, cost));
return flow;
}
int p, q;
int in[40][40];
int point(int x, int y) {
return (x - 1) * p + y;
}
void dfs(int x, int y, int u, int id) {
for (int i = 0; i < G[u].size(); ++i) {
Edge& e = edges[G[u][i]];
Edge& ne = edges[G[u][i] ^ 1];
if (e.to == s || e.to == t || e.to == u - n) continue;
if (!e.flow) continue;
e.flow--;
if (e.to > n) {
dfs(x, y, e.to, id);
return;
}
int nx, ny, dir;
if (e.to == point(x, y) + 1) {
nx = x; ny = y + 1;
dir = 1;
} else {
nx = x + 1; ny = y;
dir = 0;
}
printf("%d %d\n", id, dir);
dfs(nx, ny, e.to + n, id);
return;
}
}
int main() {
int c = read(); p = read(); q = read();
n = p * q; s = 0; t = 2 * n + 1;
for (int i = 1; i <= q; ++i) {
for (int j = 1; j <= p; ++j) {
in[i][j] = read();
if (in[i][j] == 0) add(point(i, j), point(i, j) + n, inf, 0);
if (in[i][j] == 2) {
add(point(i, j), point(i, j) + n, inf, 0);
add(point(i, j), point(i, j) + n, 1, 1);
}
}
}
if (in[1][1] != 1) add(s, 1, c, 0);
for (int i = 1; i <= q; ++i) {
for (int j = 1; j <= p; ++j) {
if (in[i][j] == 1) continue;
if (in[i][j + 1] != 1 && j + 1 <= p) add(point(i, j) + n, point(i, j + 1), inf, 0);
if (in[i + 1][j] != 1 && i + 1 <= q) add(point(i, j) + n, point(i + 1, j), inf, 0);
}
}
if (in[q][p] != 1) add(point(q, p) + n, t, c, 0);
ansflow = MaxCostMaxFlow(anscost);
for (int i = 1; i <= ansflow; ++i) {
dfs(1, 1, 1, i);
}
return 0;
}
|