HDU3613 扩展KMP

  1 #include 
  2 #include 
  3 #include 
  4 #include 
  5 #include 
  6 #include 
  7 #include 
  8 #include 
  9 #include 
 10 using namespace std;
 11 typedef long long LL;
 12 const int MOD = 1000000007;
 13 const int maxn = 40009 + 5;
 14 
 15 int value[30];
 16 int sum[500009], Next[500009], extend1[500009], extend2[500009];
 17 char a[500009], b[500009];
 18 
 19 void GetNext(char T[], int &m, int Next[])
 20 {
 21     int a = 0, p = 0;
 22     Next[0] = m;
 23 
 24     for (int i = 1; i < m; i++)
 25     {
 26         if (i >= p || i + Next[i - a] >= p)
 27         {
 28             if (i >= p)
 29                 p = i;
 30 
 31             while (p < m && T[p] == T[p - i])
 32                 p++;
 33 
 34             Next[i] = p - i;
 35             a = i;
 36         }
 37         else
 38         {
 39             Next[i] = Next[i - a];
 40         }
 41     }
 42 }
 43 
 44 void GetExtend(char s[], int &n, char t[], int &m, int extend[], int Next[])
 45 {
 46     int a = 0, p = 0;
 47     GetNext(t, m, Next);
 48 
 49     for (int i = 0; i < n; i++)
 50     {
 51         if (i >= p || i + Next[i - a] >= p)
 52         {
 53             if (i >= p)
 54             {
 55                 p = i;
 56             }
 57 
 58             while (p < n && p - i < m && s[p] == t[p - i])
 59             {
 60                 p++;
 61             }
 62 
 63             extend[i] = p - i;
 64             a = i;
 65         }
 66         else
 67         {
 68             extend[i] = Next[i - a];
 69         }
 70     }
 71 }
 72 
 73 int main()
 74 {
 75 
 76     int mid1, mid2, head, k, i, j, t;
 77 
 78     scanf("%d", &t);
 79     while (t--)
 80     {
 81         for (i = 0; i < 26; i++)
 82             scanf("%d", &value[i]);
 83 
 84         scanf(" %s", a);
 85         k = strlen(a);
 86 
 87         sum[0] = value[a[0] - 'a'];
 88         for (i = 1; i < k; i++)
 89         {
 90             sum[i] = sum[i - 1] + value[a[i] - 'a'];
 91         }
 92 
 93         for (i = 0; i < k; i++)
 94             b[i] = a[k - 1 - i];
 95 
 96         GetExtend(a, k, b, k, extend1, Next);
 97         GetExtend(b, k, a, k, extend2, Next);
 98 /*
 99         cout << "next:   ";
100         for (int i = 0; i < k; i++)
101             cout << Next[i] << " ";
102 
103         // 打印 extend
104         cout << "\nextend: ";
105         for (int i = 0; i < k; i++)
106             cout << extend[i] << " ";
107 
108         cout << endl
109              << endl;
110 */
111         head = 0;
112         for (i = 1; i < k - 1; i++)
113         {
114             if (extend1[i] == k - i)
115             {
116                 mid2 = sum[k - 1] - sum[i - 1];
117             }
118             else
119             {
120                 mid2 = 0;
121             }
122 
123             if (k - i + extend2[k - i] == k)
124             {
125                 mid1 = sum[i - 1];
126             }
127             else
128             {
129                 mid1 = 0;
130             }
131         //    cout << i << " : " << mid1 << " " << mid2 << endl;
132             if (mid1 + mid2 > head)
133                 head = mid1 + mid2;
134         }
135         printf("%d\n", head);
136     }
137 
138     return 0;
139 }