HDU 3335 Divisibility (DLX)

  1 #include <iostream>
  2 #include <string>
  3 #include <cstring>
  4 #include <cstdio>
  5 using    namespace    std;
  6 
  7 const    int    HEAD = 0;
  8 const    int    SIZE = 1005 * 1005;
  9 
 10 int    N,ANS;
 11 int    U[SIZE],D[SIZE],L[SIZE],R[SIZE],C[1005];
 12 
 13 void    ini(void);
 14 void    dancing(int);
 15 void    remove(int);
 16 void    resume(int);
 17 int    cut(void);
 18 void    debug(int);
 19 int    main(void)
 20 {
 21     int        t;
 22     long    long    s[1005];
 23 
 24     //freopen("txt.txt","r",stdin);
 25     scanf("%d",&t);
 26     while(t --)
 27     {
 28         scanf("%d",&N);
 29         for(int i = 1;i <= N;i ++)
 30             scanf("%lld",&s[i]);
 31 
 32         ini();
 33         int    count = N + 1;
 34         for(int i = 1;i <= N;i ++)
 35         {
 36             int    first = count;
 37             for(int j = 1;j <= N;j ++)
 38                 if(s[i] % s[j] == 0 || s[j] % s[i] == 0)
 39                 {
 40                     U[count] = U[j];
 41                     D[count] = j;
 42                     L[count] = count - 1;
 43                     R[count] = count + 1;
 44 
 45                     D[U[count]] = count;
 46                     U[j] = count;
 47                     C[count] = j;
 48 
 49                     count ++;
 50                 }
 51             L[first] = count - 1;
 52             R[count - 1] = first;
 53         }
 54         dancing(0);
 55         printf("%d\n",ANS);
 56     }
 57 
 58     return    0;
 59 }
 60 
 61 
 62 void    ini(void)
 63 {
 64     ANS = 0;
 65     R[HEAD] = 1;
 66     L[HEAD] = N;
 67     for(int i = 1;i <= N;i ++)
 68     {
 69         L[i] = i - 1;
 70         R[i] = i + 1;
 71         U[i] = D[i] = C[i] = i;
 72     }
 73     R[N] = 0;
 74 }
 75 
 76 void    dancing(int k)
 77 {
 78     if(k + cut() <= ANS)
 79         return    ;
 80     if(R[HEAD] == HEAD)
 81     {
 82         ANS = ANS > k ? ANS : k;
 83         return    ;
 84     }
 85 
 86     int    c = R[HEAD];
 87 
 88     for(int i = D[c];i != c;i = D[i])
 89     {
 90         remove(i);
 91         for(int j = R[i];j != i;j = R[j])
 92             remove(j);
 93         dancing(k + 1);
 94         for(int j = L[i];j != i;j = L[j])
 95             resume(j);
 96         resume(i);
 97     }
 98 
 99     return    ;
100 }
101 
102 void    remove(int c)
103 {
104     for(int i = D[c];i != c;i = D[i])
105     {
106         L[R[i]] = L[i];
107         R[L[i]] = R[i];
108     }
109 }
110 
111 void    resume(int c)
112 {
113     for(int i = U[c];i != c;i = U[i])
114     {
115         L[R[i]] = i;
116         R[L[i]] = i;
117     }
118 }
119 
120 void    debug(int count)
121 {
122     for(int i = 0;i <= count;i ++)
123         printf("U[%d]=%d D[%d]=%d L[%d]=%d R[%d]=%d c[%d]=%d\n",i,U[i],i,D[i],i,L[i],i,R[i],i,C[i]);
124     return    ;
125 }
126 
127 int    cut(void)
128 {
129     int    sum = 0;
130     for(int i = R[HEAD];i;i = R[i])
131         sum ++;
132     return    sum;
133 }