【HDOJ】3518 Boring Counting

后缀数组2倍增可解。

 #include <cstdio>
 #include <cstring>
 #include <cstdlib>

 #define MAXN 1005
 #define INF 0xfffff
 #define MAXM 27

 int wa[MAXN], wb[MAXN], ws[MAXN], wv[MAXN];
 char s[MAXN];
 int str[MAXN], sa[MAXN];
 int height[MAXN], rank[MAXN];

 int max(int a, int b) {
     return a>b ? a:b;
 }

 int min(int a, int b) {
     return a<b ? a:b;
 }

 int cmp(int *r, int a, int b, int l) {
     return r[a]==r[b] && r[a+l]==r[b+l];
 }

 void da(int *r, int *sa, int n, int m) {
     int i, j, *x = wa, *y = wb, *t;
     int p;

     for (i=; i<m; ++i) ws[i] = ;
     for (i=; i<n; ++i) ws[x[i]=r[i]]++;
     for (i=; i<m; ++i) ws[i] += ws[i-];
     for (i=n-; i>=; --i) sa[--ws[x[i]]] = i;
     for (j=, p=; j<n; j*=, m=p) {
         for (p=, i=n-j; i<n; ++i) y[p++] = i;
         for (i=; i<n; ++i) if (sa[i] >= j) y[p++] = sa[i] - j;
         for (i=; i<n; ++i) wv[i] = x[y[i]];
         for (i=; i<m; ++i) ws[i] = ;
         for (i=; i<n; ++i) ws[wv[i]]++;
         for (i=; i<m; ++i) ws[i] += ws[i-];
         for (i=n-; i>=; --i) sa[--ws[wv[i]]] = y[i];
         for (t=x, x=y, y=t, p=, x[sa[]]=, i=; i<n; ++i)
             x[sa[i]] = cmp(y, sa[i-], sa[i], j) ? p- : p++;
     }
 }

 void calheight(int *r, int *sa, int n) {
     int i, j, k = ;

     for (i=; i<=n; ++i) rank[sa[i]] = i;
     for (i=; i<n; height[rank[i++]]=k)
         for (k? --k:, j=sa[rank[i]-]; r[i+k]==r[j+k]; ++k)
             /*do nothing*/;
 }

 int getRepeat(int len, int n) {
     int i, maxx, minn;
     int ret = ;

     maxx = -;
     minn = INF;

     for (i=; i<=n; ++i) {
         if (height[i] >= len) {
             maxx = max(sa[i], max(sa[i-], maxx));
             minn = min(sa[i], min(sa[i-], minn));
         } else {
             if (maxx!=- && minn!=INF && (maxx-minn)>=len)
                 ++ret;
             maxx = -;
             minn = INF;
         }
     }

     if (maxx!=- && minn!=INF && (maxx-minn)>=len)
         ++ret;

     return ret;
 }

 void printRank(int n) {
     int i;

     printf("print rank...\n");
     for (i=; i<=n; ++i)
         printf("%d ", rank[i]);
     printf("\n");
 }

 void printHeight(int n) {
     int i;

     printf("print height...\n");
     for (i=; i<=n; ++i)
         printf("%d ", height[i]);
     printf("\n");
 }

 void printSa(int n) {
     int i;

     printf("print sa...\n");
     for (i=; i<=n; ++i)
         printf("%d ", sa[i]);
     printf("\n");
 }

 int main() {
     int i, len;
     int ans;

 #ifndef ONLINE_JUDGE
     freopen("data.in", "r", stdin);
     freopen("data.out", "w", stdout);
 #endif

     while (scanf("%s",s)!=EOF && (s[]!='#')) {
         //printf("%s\n", s);
         for (i=; s[i]; ++i)
             str[i] = s[i] - 'a' + ;
         str[i] = ;
         len = i;
         da(str, sa, len+, MAXM);
         calheight(str, sa, len);
 #ifndef ONLINE_JUDGE
         printSa(len);
         printRank(len);
         printHeight(len);
 #endif
         for (ans=, i=; i<=len/; ++i) {
             ans += getRepeat(i, len);
         }
         printf("%d\n", ans);
     }

     return ;
 }