POJ1149 PIGS

想了好久啊。。。(#-.-)

开始想到m*n个点的构图,明显超时,于是考虑压缩节点个数

我们发现每个猪圈最后被有且只有一个人调整,于是想到对于一个人,连接他能调整的每个猪圈的上一个控制人。(不懂可以开代码  (・(ェ)・)   )

/**
* Problem:POJ1149
* Author:Shun Yao
* Time:2013.9.13
* Result:
* Memo:
*/ #include <cstring>
#include <cstdio> #define INF 0x7fffffff
#define MAXT 1111 long m, n, s, t, f[MAXT], p2[MAXT], h[MAXT], sum[MAXT]; class Edge {
public:
long v, f;
Edge *op, *next;
Edge() {}
~Edge() {}
Edge(long V, long F, Edge *o, Edge *ne) : v(V), f(F), op(o), next(ne) {}
} *g[MAXT], *now[MAXT], *p1[MAXT]; void add(long x, long y, long c) {
g[x] = new Edge(y, c, 0, g[x]);
g[y] = new Edge(x, 0, g[x], g[y]);
g[x]->op = g[y];
} long *l, *r, q[MAXT];
void SAP() {
static char f;
static Edge *e;
static long i, ans, ww, w;
memset(h, -1, sizeof h);
memset(sum, 0, sizeof sum);
l = r = q;
*r++ = t;
h[t] = 0;
sum[0] = 1;
while (l < r) {
for (e = g[*l]; e; e = e->next)
if (h[e->v] == -1) {
++sum[h[e->v] = h[*l] + 1];
*r++ = e->v;
}
++l;
}
for (i = 0; i <= t; ++i) {
now[i] = g[i];
p1[i] = 0;
p2[i] = -1;
}
i = s;
ans = 0;
while (h[s] <= t) {
f = 0;
for (e = now[i]; e; e = e->next)
if (e->f > 0 && h[i] == h[e->v] + 1) {
now[i] = e;
p1[e->v] = e;
p2[e->v] = i;
i = e->v;
if (i == t) {
ww = INF;
for (w = t; w != s; w = p2[w])
if (ww > p1[w]->f)
ww = p1[w]->f;
for (w = t; w != s; w = p2[w]) {
p1[w]->f -= ww;
p1[w]->op->f += ww;
}
ans += ww;
i = s;
}
f = 1;
break;
}
if (!f) {
ww = t + 1;
for (e = g[i]; e; e = e->next)
if (e->f > 0 && ww > h[e->v]) {
ww = h[e->v];
now[i] = e;
}
++sum[ww > t ? ww : ++ww];
if (!--sum[h[i]])
break;
h[i] = ww;
if (i != s)
i = p2[i];
}
}
printf("%ld", ans);
} int main() {
static long i, j, k, A, B; #ifndef ONLINE_JUDGE
freopen("poj1149.in", "r", stdin);
freopen("poj1149.out", "w", stdout);
#endif scanf("%ld%ld", &m, &n);
s = 0;
t = n + m + 1;
for (i = 1; i <= m; ++i) {
scanf("%ld", &A);
add(s, i, A);
f[i] = i;
}
for (i = 1; i <= n; ++i) {
scanf("%ld", &A);
for (j = 1; j <= A; ++j) {
scanf("%ld", &k);
add(f[k], i + m, INF);
f[k] = i + m;
}
scanf("%ld", &B);
add(i + m, t, B);
}
SAP(); fclose(stdin);
fclose(stdout);
return 0;
}
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