# BZOJ2595 [Wc2008]游览计划

  1 /**************************************************************
2     Problem: 2595
3     User: rausen
4     Language: C++
5     Result: Accepted
6     Time:160 ms
7     Memory:4444 kb
8 ****************************************************************/
9
10 #include <cstdio>
11 #include <queue>
12 #include <utility>
13
14 #define P Point
15 using namespace std;
16 const int N = 15;
17 const int maxS = 1024;
18 const int inf = 1e9;
19 const int dx[4] = {0, 0, 1, -1};
20 const int dy[4] = {1, -1, 0, 0};
21
22 int n, m, K;
23 int a[N][N], bin[N];
24 int f[N][N][maxS];
25 bool inq[N][N], used[N][N];
26
27 struct Point {
28     int x, y;
29     P() {}
30     P(int _x, int _y) : x(_x), y(_y) {}
31 };
32 queue<P> q;
33
34 struct Path {
35     int x, y, s;
36     Path() {}
37     Path(int _f, int _s, int _t) : x(_f), y(_s), s(_t) {}
38 } path[N][N][maxS];
39
41     int x = 0;
42     char ch = getchar();
43     while (ch < '0' || '9' < ch)
44         ch = getchar();
45     while ('0' <= ch && ch <= '9') {
46         x = x * 10 + ch - '0';
47         ch = getchar();
48     }
49     return x;
50 }
51
52 void spfa(int S) {
53     int k, x, y, X, Y;
54     while (!q.empty()) {
55         inq[x = q.front().x][y = q.front().y] = 0, q.pop();
56         for (k = 0; k < 4; ++k) {
57             X = x + dx[k], Y = y + dy[k];
58             if (x < 1 || y < 1 || x > n || y > m) continue;
59             if (f[X][Y][S] > f[x][y][S] + a[X][Y]) {
60                 f[X][Y][S] = f[x][y][S] + a[X][Y];
61                 path[X][Y][S] = Path(x, y, S);
62                 if (!inq[X][Y])
63                     q.push(P(X, Y)), inq[X][Y] = 1;
64             }
65         }
66     }
67 }
68
69 #define t path[x][y][S]
70 void dfs(int x, int y, int S) {
71     if (x > inf || !path[x][y][S].s) return;
72     used[x][y] = 1;
73     dfs(t.x, t.y, t.s);
74     if (t.x == x && t.y == y) dfs(x, y, S ^ t.s);
75 }
76 #undef t
77
79     int i, j;
81     for (i = 1; i <= n; ++i)
82         for (j = 1; j <= m; ++j)
83             if (!(a[i][j] = read())) ++K;
84     for (i = bin[0] = 1; i <= K; ++i)
85         bin[i] = bin[i - 1] << 1;
86 }
87
88 void pre_work() {
89     int i, j, k;
90     for (i = 1; i <= n; ++i)
91         for (j = 1; j <= m; ++j)
92             for (k = 0; k < bin[K]; ++k)
93                 f[i][j][k] = path[i][j][k].x = inf;
94     for (i = 1, K = 0; i <= n; ++i)
95         for (j = 1; j <= m; ++j)
96             if (!a[i][j])
97                 f[i][j][bin[K++]] = 0;
98 }
99
100 void work() {
101     int i, j, S, s, tmp;
102     for (S = 1; S < bin[K]; spfa(S++))
103         for (i = 1; i <= n; ++i)
104             for (j = 1; j <= m; ++j) {
105                 for (s = S & (S - 1); s; s = S & (s - 1))
106                     if ((tmp = f[i][j][s] + f[i][j][S ^ s] - a[i][j]) < f[i][j][S]) {
107                         f[i][j][S] = tmp;
108                         path[i][j][S] = Path(i, j, s);
109                     }
110                 if (f[i][j][S] != inf) {
111                     q.push(P(i, j)), inq[i][j] = 1;
112                 }
113             }
114 }
115
116 void get_ans1() {
117     int i, j;
118     for (i = 1; i <= n; ++i)
119         for (j = 1; j <= m; ++j) if (!a[i][j]) {
120             dfs(i, j, bin[K] - 1);
121             printf("%d\n", f[i][j][bin[K] - 1]);
122             return;
123         }
124 }
125
126 void get_ans2() {
127     int i, j;
128     for (i = 1; i <= n; ++i, putchar('\n'))
129         for (j = 1; j <= m; ++j)
130             if (!a[i][j]) putchar('x'); else
131             if (used[i][j]) putchar('o'); else
132             putchar('_');
133
134 }
135
136 int main() {
143 }