BZOJ 2744: [HEOI2012]朋友圈

  1 #include <cstdio>
  2 
  3 inline char Char(void)
  4 {
  5     static const int siz = 1024;
  6     
  7     static char buf[siz];
  8     static char *hd = buf + siz;
  9     static char *tl = buf + siz;
 10     
 11     if (hd == tl)
 12         fread(hd = buf, 1, siz, stdin);
 13     
 14     return *hd++;
 15 }
 16 
 17 inline int Int(void)
 18 {
 19     int ret = 0, neg = 0, c = Char();
 20     
 21     for (; c < 48; c = Char())
 22         if (c == ‘-‘)neg ^= 1;
 23     
 24     for (; c > 47; c = Char())
 25         ret = ret * 10 + c - 48;
 26     
 27     return neg ? -ret : ret;
 28 }
 29 
 30 const int maxn = 3005;
 31 const int maxm = 9000005;
 32 
 33 int A, B, E;
 34 int a[maxn];
 35 int b[maxn];
 36 
 37 bool mp[maxn][maxn];
 38 
 39 inline int count(int x)
 40 {
 41     int ret = 0;
 42     
 43     while (x)
 44         x -= x&-x, ++ret;
 45     
 46     return ret;
 47 }
 48 
 49 inline bool check(int x, int y)
 50 {
 51     if (count(x | y) & 1)
 52         return false;
 53     
 54     return true;
 55 }
 56 
 57 int hd[maxn];
 58 int to[maxm];
 59 int nt[maxm];
 60 
 61 inline void addEdge(int x, int y)
 62 {
 63     static int tot = 0;
 64     nt[++tot] = hd[x]; to[tot] = y; hd[x] = tot;
 65 }
 66 
 67 int tim0;
 68 int tim1;
 69 int ill[maxn];
 70 int vis[maxn];
 71 int mch[maxn];
 72 
 73 bool dfs(int u)
 74 {
 75     if (u == 0)return true;
 76     
 77     for (int i = hd[u], v; i; i = nt[i])
 78         if (ill[v = to[i]] != tim0)
 79         {
 80             if (vis[v] == tim1)
 81                 continue;
 82             vis[v] = tim1;
 83             if (dfs(mch[v]))
 84             {
 85                 mch[v] = u;
 86                 return true;
 87             }
 88         }
 89     
 90     return false;
 91 }
 92 
 93 inline int calc(int x = 0, int y = 0)
 94 {
 95     int cnt = 0; ++tim0;
 96     
 97     for (int i = 1; i <= B; ++i)
 98         if (!mp[x][i] || !mp[y][i])
 99             ill[i] = tim0, ++cnt;
100                 
101     for (int i = 1; i <= B; ++i)
102         mch[i] = 0;
103     
104     for (int i = 1; i <= B; ++i)
105         if (ill[i] != tim0)
106         {
107             ++tim1;
108             
109             if (dfs(i))
110                 ++cnt;
111         }
112     
113     return B - cnt;
114 }
115 
116 signed main(void)
117 {
118     A = Int();
119     B = Int();
120     E = Int();
121     
122     for (int i = 1; i <= A; ++i)
123         a[i] = Int();
124     
125     for (int i = 1; i <= B; ++i)
126         b[i] = Int();
127     
128     for (int i = 1; i <= E; ++i)
129     {
130         int x = Int();
131         int y = Int();
132         mp[x][y] = true;
133     }
134     
135     for (int i = 1; i <= B; ++i)
136         mp[0][i] = true;
137     
138     for (int i = 1; i <= B; ++i)if (b[i] & 1)
139         for (int j = 1; j <= B; ++j)if (!(b[j] & 1))
140             if (check(b[i], b[j]))addEdge(i, j);
141     
142     int ans = calc();
143     
144     for (int i = 1; i <= A; ++i)
145     {
146         int tmp = calc(i) + 1;
147         if (tmp > ans)
148             ans = tmp;
149     }
150     
151     for (int i = 1; i <= A; ++i)if (a[i] & 1)
152         for (int j = 1; j <= A; ++j)if (!(a[j] & 1))
153         {
154             int tmp = calc(i, j) + 2;
155             if (tmp > ans)
156                 ans = tmp;
157         }
158         
159     printf("%d\n", ans);
160 }