4 minutes
[BZOJ1066][SCOI2007]蜥蜴（最大流）
这道题就是最大流，首先对柱子进行拆点，一个入点和一个出点，入点向出点连一条容量为柱子高度的边，从每个柱子的出点，向可以一次跳到的所有柱子的入点连一条容量为当前柱子高度的边，再从每个可以一次跳出的柱子向汇点连一条容量为柱子高度的边，从源点向每个有蜥蜴的柱子的入点连一条容量为1的边，然后做一次最大流即可。当然答案输出的是不能跳出的蜥蜴，我被坑了好久233
//SCOI2007 lizard.cpp
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<string>
#include<vector>
#include<queue>
#include<stack>
#include<cmath>
#include<set>
#include<map>
//#define LOCAL
#define READ_FREAD
//#define READ_FILE
//#define VISUAL_STUDIO
const int MAXN = 20;
const int MAXPT = 2 * MAXN * MAXN + 2;
const int MAXM = 170000;
#ifdef LOCAL
#define LOCAL_DEBUG
#define LOCAL_TIME
//#define STD_DEBUG
#endif
#ifdef VISUAL_STUDIO
#pragma warning(disable: 4996)
#endif
#ifdef LOCAL_TIME
#include<ctime>
#endif
#ifdef READ_FREAD
char fread_char;
inline void fread_init()
{
fread_char = getchar();
}
inline int get_int()
{
int ret = 0;
while ((fread_char < '0') || (fread_char > '9'))
{
fread_char = getchar();
}
while ((fread_char >= '0') && (fread_char <= '9'))
{
ret = ret * 10 + fread_char - '0';
fread_char = getchar();
}
return ret;
}
inline char get_char()
{
char ret;
while ((fread_char == ' ') || (fread_char == 'n'))
{
fread_char = getchar();
}
ret = fread_char;
fread_char = getchar();
return ret;
}
#endif
inline void read(int &a)
{
#ifdef READ_FREAD
a = get_int();
#else
scanf("%d", &a);
#endif
}
inline void read(char &a)
{
#ifdef READ_FREAD
a = get_char();
#else
scanf("%c", &a);
#endif
}
struct pillar_node
{
int x, y, d;
};
int graph[MAXPT][MAXPT];
inline void add_edge(const int u, const int v, const int d)
{
#ifdef LOCAL_DEBUG
printf("ADD_EDGE %d %d %dn", u, v, d);
#endif
graph[u][v] = d;
graph[v][u] = 0;
}
struct queue_node
{
int id, height;
inline queue_node(const int id_ = 0, const int height_ = 0)
{
id = id_;
height = height_;
}
inline bool operator < (const queue_node &b) const
{
return height < b.height;
}
};
int r, c, d;
int tot_lizard;
pillar_node pillar[MAXM];
int tot_pillar;
int k;
char tmp_k;
char lizard_pt;
int s, t;
int gap[MAXPT];
int height[MAXPT], inflow[MAXPT];
bool in_q[MAXPT];
bool visit[MAXPT];
std::priority_queue <queue_node> Q;
inline int in_pt(const int x, const int y)
{
return (x - 1) * c + y;
}
inline int out_pt(const int x, const int y)
{
return r * c + (x - 1) * c + y;
}
std::queue <int> bfs_q;
inline void bfs()
{
gap[0] = 1;
bfs_q.push(t);
visit[t] = true;
int tmp;
while (!bfs_q.empty())
{
tmp = bfs_q.front();
bfs_q.pop();
for (int i = s; i < t; i++)
{
if ((!visit[i]) && (graph[i][tmp] > 0))
{
height[i] = height[tmp] + 1;
gap[height[i]]++;
visit[i] = true;
bfs_q.push(i);
}
}
}
}
inline int max_flow()
{
in_q[s] = in_q[t] = true;
for (int i = s + 1; i < t; i++)
{
if (graph[s][i] > 0)
{
inflow[i] = graph[s][i];
graph[i][s] = inflow[i];
graph[s][i] = 0;
in_q[i] = true;
Q.push(queue_node(i, height[i]));
}
}
queue_node tmp;
int push_flow = -1;
int min_height = -1;
while (!Q.empty())
{
tmp = Q.top();
Q.pop();
#ifdef LOCAL_DEBUG
printf("DEBUG ID HEIGHT INFLOW: %d %d %dn", tmp.id, tmp.height, inflow[tmp.id]);
#endif
in_q[tmp.id] = false;
for (int i = s + 1; (i <= t) && (inflow[tmp.id] > 0); i++)
{
if ((graph[tmp.id][i] > 0) && (height[tmp.id] == height[i] + 1))
{
push_flow = std::min(inflow[tmp.id], graph[tmp.id][i]);
inflow[tmp.id] -= push_flow;
inflow[i] += push_flow;
graph[tmp.id][i] -= push_flow;
graph[i][tmp.id] += push_flow;
if (!in_q[i])
{
in_q[i] = true;
Q.push(queue_node(i, height[i]));
}
}
}
if (inflow[tmp.id] > 0)
{
min_height = -1;
for (int i = s + 1; i <= t; i++)
{
if (graph[tmp.id][i] > 0)
{
if ((min_height == -1) || (min_height > height[i]))
{
min_height = height[i];
}
}
}
if ((min_height > -1) && (min_height < t))
{
gap[height[tmp.id]]--;
if (gap[height[tmp.id]] == 0)
{
for (int i = s + 1; i < t; i++)
{
if ((height[i] >= height[tmp.id]) && (height[i] < t))
{
gap[height[i]]--;
height[i] = t;
if (in_q[i])
{
Q.pop();
}
}
}
}
else
{
gap[height[tmp.id] = min_height + 1]++;
in_q[tmp.id] = true;
Q.push(queue_node(tmp.id, height[tmp.id]));
}
}
}
}
return inflow[t];
}
int main()
{
#ifdef LOCAL_TIME
long long start_time_ = clock();
#endif
#ifdef READ_FILE
freopen("lizard.in", "r", stdin);
#ifndef STD_DEBUG
freopen("lizard.out", "w", stdout);
#endif
#endif
#ifdef READ_FREAD
fread_init();
#endif
read(r);
read(c);
read(d);
s = 0;
t = r * c * 2 + 1;
for (int i = 1; i <= r; i++)
{
for (int j = 1; j <= c; j++)
{
read(tmp_k);
k = tmp_k - '0';
if (k > 0)
{
pillar[tot_pillar].x = i;
pillar[tot_pillar].y = j;
pillar[tot_pillar++].d = k;
add_edge(in_pt(i, j), out_pt(i, j), k);
}
}
}
for (int i = 1; i <= r; i++)
{
for (int j = 1; j <= c; j++)
{
read(lizard_pt);
if (lizard_pt == 'L')
{
tot_lizard++;
add_edge(s, in_pt(i, j), 1);
}
}
}
for (int i = 0; i < tot_pillar; i++)
{
if ((pillar[i].x <= d) || (pillar[i].y <= d) || (r - pillar[i].x + 1 <= d) || (c - pillar[i].y + 1 <= d))
{
add_edge(out_pt(pillar[i].x, pillar[i].y), t, pillar[i].d);
}
for (int j = 0; j < tot_pillar; j++)
{
if (i == j)
{
continue;
}
if ((pillar[i].x - pillar[j].x) * (pillar[i].x - pillar[j].x) + (pillar[i].y - pillar[j].y) * (pillar[i].y - pillar[j].y) <= d * d)
{
add_edge(out_pt(pillar[i].x, pillar[i].y), in_pt(pillar[j].x, pillar[j].y), pillar[i].d);
}
}
}
bfs();
printf("%d", tot_lizard - max_flow());
#ifdef LOCAL_TIME
printf("nrun time: %lld msn", clock() - start_time_);
#endif
#ifdef READ_FILE
fclose(stdin);
#ifndef STD_DEBUG
fclose(stdout);
#endif
#endif
return 0;
}
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