后缀数组2倍增可解。
1 #include <cstdio> 2 #include <cstring> 3 #include <cstdlib> 4 5 #define MAXN 1005 6 #define INF 0xfffff 7 #define MAXM 27 8 9 int wa[MAXN], wb[MAXN], ws[MAXN], wv[MAXN]; 10 char s[MAXN]; 11 int str[MAXN], sa[MAXN]; 12 int height[MAXN], rank[MAXN]; 13 14 int max(int a, int b) { 15 return a>b ? a:b; 16 } 17 18 int min(int a, int b) { 19 return a<b ? a:b; 20 } 21 22 int cmp(int *r, int a, int b, int l) { 23 return r[a]==r[b] && r[a+l]==r[b+l]; 24 } 25 26 void da(int *r, int *sa, int n, int m) { 27 int i, j, *x = wa, *y = wb, *t; 28 int p; 29 30 for (i=0; i<m; ++i) ws[i] = 0; 31 for (i=0; i<n; ++i) ws[x[i]=r[i]]++; 32 for (i=1; i<m; ++i) ws[i] += ws[i-1]; 33 for (i=n-1; i>=0; --i) sa[--ws[x[i]]] = i; 34 for (j=1, p=1; j<n; j*=2, m=p) { 35 for (p=0, i=n-j; i<n; ++i) y[p++] = i; 36 for (i=0; i<n; ++i) if (sa[i] >= j) y[p++] = sa[i] - j; 37 for (i=0; i<n; ++i) wv[i] = x[y[i]]; 38 for (i=0; i<m; ++i) ws[i] = 0; 39 for (i=0; i<n; ++i) ws[wv[i]]++; 40 for (i=1; i<m; ++i) ws[i] += ws[i-1]; 41 for (i=n-1; i>=0; --i) sa[--ws[wv[i]]] = y[i]; 42 for (t=x, x=y, y=t, p=1, x[sa[0]]=0, i=1; i<n; ++i) 43 x[sa[i]] = cmp(y, sa[i-1], sa[i], j) ? p-1 : p++; 44 } 45 } 46 47 void calheight(int *r, int *sa, int n) { 48 int i, j, k = 0; 49 50 for (i=1; i<=n; ++i) rank[sa[i]] = i; 51 for (i=0; i<n; height[rank[i++]]=k) 52 for (k? --k:0, j=sa[rank[i]-1]; r[i+k]==r[j+k]; ++k) 53 /*do nothing*/; 54 } 55 56 int getRepeat(int len, int n) { 57 int i, maxx, minn; 58 int ret = 0; 59 60 maxx = -1; 61 minn = INF; 62 63 for (i=1; i<=n; ++i) { 64 if (height[i] >= len) { 65 maxx = max(sa[i], max(sa[i-1], maxx)); 66 minn = min(sa[i], min(sa[i-1], minn)); 67 } else { 68 if (maxx!=-1 && minn!=INF && (maxx-minn)>=len) 69 ++ret; 70 maxx = -1; 71 minn = INF; 72 } 73 } 74 75 if (maxx!=-1 && minn!=INF && (maxx-minn)>=len) 76 ++ret; 77 78 return ret; 79 } 80 81 void printRank(int n) { 82 int i; 83 84 printf("print rank...\n"); 85 for (i=1; i<=n; ++i) 86 printf("%d ", rank[i]); 87 printf("\n"); 88 } 89 90 void printHeight(int n) { 91 int i; 92 93 printf("print height...\n"); 94 for (i=1; i<=n; ++i) 95 printf("%d ", height[i]); 96 printf("\n"); 97 } 98 99 void printSa(int n) { 100 int i; 101 102 printf("print sa...\n"); 103 for (i=0; i<=n; ++i) 104 printf("%d ", sa[i]); 105 printf("\n"); 106 } 107 108 int main() { 109 int i, len; 110 int ans; 111 112 #ifndef ONLINE_JUDGE 113 freopen("data.in", "r", stdin); 114 freopen("data.out", "w", stdout); 115 #endif 116 117 while (scanf("%s",s)!=EOF && (s[0]!=‘#‘)) { 118 //printf("%s\n", s); 119 for (i=0; s[i]; ++i) 120 str[i] = s[i] - ‘a‘ + 1; 121 str[i] = 0; 122 len = i; 123 da(str, sa, len+1, MAXM); 124 calheight(str, sa, len); 125 #ifndef ONLINE_JUDGE 126 printSa(len); 127 printRank(len); 128 printHeight(len); 129 #endif 130 for (ans=0, i=1; i<=len/2; ++i) { 131 ans += getRepeat(i, len); 132 } 133 printf("%d\n", ans); 134 } 135 136 return 0; 137 }
时间: 2024-10-12 22:41:54