POJ 1275 Cashier Employment(差分约束)

题目链接

详情请看黑书第306页。。。完全根据书做的，我把s[-1]改为s[24]了。

  1 #include <cstdio>
  2 #include <cstring>
  3 #include <cmath>
  4 #include <string>
  5 #include <ctime>
  6 #include <queue>
  7 #include <vector>
  8 using namespace std;
  9 #define INF 10000000
 10 struct node
 11 {
 12     int u,v,w,next;
 13 }edge[100*100];
 14 int first[101],in[101],dis[101],num[101];
 15 int t;
 16 int s[31],r[31],ti[31];
 17 void CL()
 18 {
 19     t = 1;
 20     memset(first,-1,sizeof(first));
 21 }
 22 void add(int u,int v,int w)
 23 {
 24     edge[t].u = u;
 25     edge[t].v = v;
 26     edge[t].w = w;
 27     edge[t].next = first[u];
 28     first[u] = t ++;
 29 }
 30 int spfa()
 31 {
 32     int i,u,v;
 33     for(i = 0;i <= 24;i ++)
 34     {
 35         dis[i] = -INF;
 36         in[i] = 0;
 37         num[i] = 0;
 38     }
 39     queue<int> que;
 40     que.push(24);
 41     in[24] = 1;
 42     dis[24] = 0;
 43     num[24] = 1;
 44     while(!que.empty())
 45     {
 46         u = que.front();
 47         in[u] = 0;
 48         que.pop();
 49         for(i = first[u];i != -1;i = edge[i].next)
 50         {
 51             v = edge[i].v;
 52             if(dis[v] < dis[u] + edge[i].w)
 53             {
 54                 dis[v] = dis[u] + edge[i].w;
 55                 if(!in[v])
 56                 {
 57                     in[v] = 1;
 58                     que.push(v);
 59                     num[v] ++;
 60                     if(num[v] > 24)
 61                     return 1;
 62                 }
 63             }
 64         }
 65     }
 66     return 0;
 67 }
 68 int judge(int mid)
 69 {
 70     CL();
 71     int i,j;
 72     for(i = 1;i <= 23;i ++)
 73     {
 74         add(i-1,i,0);
 75         add(i,i-1,-ti[i]);
 76     }
 77     add(24,0,0);
 78     add(0,24,-ti[0]);
 79     add(24,23,mid);
 80     for(j = 0;j <= 23;j ++)
 81     {
 82         i = (j + 8)%24;
 83         if(i > j)
 84         add(j,i,r[i]);
 85         else
 86         add(j,i,r[i]-mid);
 87     }
 88     if(!spfa()&&dis[23] == mid)
 89     return 1;
 90     else
 91     return 0;
 92 }
 93 int main()
 94 {
 95     int i,j,cas,n,maxz;
 96     scanf("%d",&cas);
 97     while(cas --)
 98     {
 99         maxz = 0;
100         for(i = 0;i < 24;i ++)
101         {
102             scanf("%d",&r[i]);
103             if(maxz < r[i])
104             maxz = r[i];
105         }
106         scanf("%d",&n);
107         for(i = 0;i < n;i ++)
108         {
109             scanf("%d",&j);
110             ti[j] ++;
111         }
112         for(i = 0;i <= n;i ++)
113         {
114             if(judge(i))
115             {
116                 printf("%d\n",i);
117                 break;
118             }
119         }
120         if(i == n+1)
121         printf("No Solution\n");
122     }
123     return 0;
124 }

 

posted @ 2013-03-08 11:48  Naix_x  阅读(199)  评论(0)    收藏  举报