poj 1149

 

　　

  1 #include <cstdio>

  2 #include <cstring>

  3 #include <queue>

  4 #define _clr(x, y) memset(x, y, sizeof(x))

  5 #define Min(x, y) (x < y ? x : y)

  6 #define INF 0x3f3f3f3f

  7 #define N 150

  8 #define M 1005

  9 using namespace std;

 10 

 11 int resi[N][N], h[N], ef[N];

 12 int dist[N], pre[N];

 13 int Maxf, S, T;

 14 bool used[N];

 15 queue<int> Q;

 16 

 17 //  一般预流推进算法 --47ms

 18 void Push(int x)

 19 {

 20     for(int i=0; i<=T; i++)

 21     {

 22         int tmp = Min(ef[x], resi[x][i]);

 23         if(tmp>0 && (x==S || h[x]==h[i]+1))

 24         {

 25             resi[x][i] -= tmp, resi[i][x] += tmp;

 26             ef[x] -= tmp, ef[i] += tmp;

 27             if(i==T) Maxf += tmp;

 28             if(i!=S && i!=T) Q.push(i);

 29         }

 30     }

 31 }

 32 

 33 void Push_Relabel(int n)

 34 {

 35     Maxf = 0;

 36     _clr(ef, 0);

 37     _clr(h, 0);

 38     h[S] = n, ef[S]=INF, ef[T]=-INF;

 39     Q.push(S);

 40     while(!Q.empty())

 41     {

 42         int x = Q.front();

 43         Q.pop();

 44         Push(x);

 45         if(x!=S && x!=T && ef[x]>0)

 46         {

 47             h[x]++;

 48             Q.push(x);

 49         }

 50     }

 51     printf("%d\n",Maxf);

 52 }

 53 

 54 void Init(int m, int n)

 55 {   

 56     int pig[M], last[M];

 57     int num, k;

 58     S=0, T=n+1;

 59     _clr(last, 0);

 60     _clr(resi, 0);

 61     for(int i=1; i<=m; i++)

 62        scanf("%d", pig+i);

 63     for(int i=1; i<=n; i++)

 64     {

 65         scanf("%d", &num);

 66         for(int j=0; j<num; j++)

 67         {

 68             scanf("%d", &k);

 69             if(last[k]==0)

 70                 resi[S][i] += pig[k];

 71             else

 72                 resi[last[k]][i] = INF;

 73             last[k] = i;

 74         }

 75         scanf("%d", resi[i]+T);

 76     }

 77 }

 78 

 79 // 连续最短曾广路算法  --17ms

 80 bool bfs_dinic()

 81 {

 82     _clr(dist, -1);

 83     dist[S] = 0;

 84     Q.push(S);

 85     while(!Q.empty())

 86     {

 87         int u = Q.front();

 88         Q.pop();

 89         for(int i=0; i<=T; i++)

 90         {

 91             if(dist[i]<0 && resi[u][i])

 92             {

 93                 dist[i] = dist[u]+1;

 94                 Q.push(i);

 95             }

 96         }

 97     }

 98     return dist[T]>0 ? 1 : 0;

 99 }

100 

101 int dfs(int x, int f)

102 {

103     int a=0;

104     if(x==T) return f;

105     for(int i=0; i<=T; i++)

106     {

107         if(resi[x][i] && dist[i]==dist[x]+1 && (a=dfs(i, Min(f, resi[x][i]))))

108         {

109             resi[x][i] -= a, resi[i][x] += a;

110             return a;

111         }

112     }

113     return 0;

114 }

115 

116 void Dinic()

117 {

118     int ans=0, a;

119     while(bfs_dinic())

120         while(a=dfs(0, INF)) ans+= a;

121     printf("%d\n", ans);

122 }

123 

124 //  EK算法   --0ms

125 bool bfs()

126 {

127     _clr(used, 0);

128     _clr(pre, -1);

129     int Sta[N], top=0;

130     used[S] = true;

131     Sta[top++] = S;

132     while(top)

133     {

134         int u = Sta[--top];

135         for(int i=0; i<=T; i++)

136         {

137             if(resi[u][i] && !used[i])

138             {

139                 used[i] = true;

140                 pre[i] = u;

141                 if(i==T) return true;

142                 Sta[top++] = i;

143             }

144         }

145     }

146     return false;

147 }

148 void EK()

149 {

150     int maxf=0, d;

151     while(bfs())

152     {

153         d = INF;

154         for(int i=T; i!=S; i=pre[i])

155             d = Min(d, resi[pre[i]][i]);

156         for(int i=T; i!=S; i=pre[i])

157         {

158             resi[pre[i]][i] -= d;

159             resi[i][pre[i]] += d;

160         }

161         maxf += d;

162     }

163     printf("%d\n", maxf);

164 }

165 int main()

166 {

167     int n, m;

168     while(~scanf("%d%d", &m, &n))

169     {

170         while(!Q.empty()) Q.pop();

171         Init(m, n);

172         EK();

173         //Push_Relabel(n);

174         //Dinic();

175     }

176     return 0;

177 }