poj 3415 , poj 3581，BZOJ 3538

后缀数组总结:http://blog.csdn.net/crazy_ac/article/details/9666833

poj 3415char s1[N],s2[N];  int val[N],num[N];  __int64 solve(int n,int len,int k,int flag)  {      int tot , top = 0;      __int64 ans = 0 ,sum;      for(int i=1;i<=n;i++)      {          if(h[i]<k) sum = tot = top = 0;          else          {              tot = 0;              if((sa[i-1]>len)^flag) tot=1,sum+=h[i]-k+1;              while(top>0 && val[top] >= h[i])              {                  sum -= (__int64) (val[top] - h[i]) * num[top];                  tot += num[top];                  top --;              }              num[++top] = tot;              val[top] = h[i];              if((sa[i] < len)^flag) ans  += sum;          }      }      return ans;  }  int main()  {      int k;      scanf("%d",&k);      while(scanf("%d",&k),k)      {          scanf("%s%s",s1,s2);          int len1 = strlen(s1);          int len2 = strlen(s2);          for(int i=0;i<len1;i++) a[i]=s1[i];          a[len1] = '$';          for(int i=0;i<len2;i++) a[i+len1+1]=s2[i];          int n = len1 + len2 + 1; a[n] = 0;          suffix(n+1);          printf("%I64d\n",solve(n,len1,k,0) + solve(n,len1,k,1));      }      return 0;  }  

poj 3581#include <cstdio>    #include <cstring>    #include <algorithm>    const int N = 444444;    using std::reverse_copy;    int a[N] , b[N];    int min_p(int *s,int n,int p)    {        int i = p, j = p+1;        while(true)        {            if(i >= n || j >= n) break;            int k = 0;            for(;k<n&&i<n&&j<n&&s[i+k]==s[j+k];k++);            if(k >= n) break;            if(s[i+k] > s[j+k])            {                i += k + 1;            }            else            {                j += k + 1;            }            if(i == j) j++;        }        return std::min(i,j);    }        int main()    {        int n;        scanf("%d",&n);        for(int i = 0; i < n; i++) scanf("%d",&a[i]);        reverse_copy(a,a+n,b);        reverse_copy(a,a+n,b+n);        int p1 = n - 1 - min_p(b,n,2);        reverse_copy(a+p1+1,a+n,b);        reverse_copy(a+p1+1,a+n,b+n-p1-1);        int p2 = n-p1-1 - min_p(b,n-p1-1,1);        p2 = p1 + p2;        for(int i = p1; i >= 0; i--) printf("%d\n",a[i]);        for(int i = p2; i > p1; i--) printf("%d\n",a[i]);        for(int i = n-1;i > p2; i--) printf("%d\n",a[i]);        puts("");        return 0;    }    

BZOJ 3538

struct node {    int l,r,vi;    node () {}    node(int _l,int _r,int _vi):l(_l),r(_r),vi(_vi) {}};node st[N];int top ;long long sum[N];long long ans;void dfs(int l,int r){    top = 0;    st[++top] = node(l,r,0);    while(top > 0)    {        node tmp = st[top];        if(tmp.l == tmp.r || tmp.vi == 2)        {            top--;            continue;        }        if(tmp.vi == 0)        {            int l = tmp.l, r = tmp.r;            st[top].vi++;            int m = rmq(l+1,r,h);            ans += (long long) (m-l)*(sum[r]-sum[m-1]) + (long long)(r-m+1)*(sum[m-1]-sum[l-1]) ;            ans -= 2LL * h[m] * (r-m+1) * (m - l);            if(l!=m-1)st[++top] = node(l,m-1,0);        }        else        {            st[top].vi++;            int m = rmq(tmp.l+1,tmp.r,h);            st[++top] = node(m,tmp.r,0);        }    }}char s[N];int main(){    ans = 0;    LOG[0] = -1;    for(int i = 1; i < N; i++) LOG[i] = LOG[i>>1] + 1;    scanf("%s",s);    int n = strlen(s);    for(int i = 0; i < n; i++) a[i] = s[i];    a[n] = 0;    suffix(n+1,128);    sum[0] = 0;    for(int i = 1; i <= n; i++)sum[i] = sum[i-1] + n - sa[i];    rmq_init(h,n);    dfs(1,n);    printf("%lld\n",ans);    return 0;}