Colorful String

Colorful String

 #include <bits/stdc++.h>
 using namespace std;
 typedef long long ll;
 const int maxn = 1e6+;
 char s[maxn];
 int n;
 int record[maxn];  // 记录i结点在原字符串的位置
 int sum[maxn*];
 void pushup(int rt) {
     sum[rt] |= sum[rt*];
     sum[rt] |= sum[rt*+];
 }
 void build(int l, int r, int rt) {
     if (l == r) {
         sum[rt] |= <<(s[l]-'a');
         return;
     }
     int mid = (l+r)/;
     build(l,mid,rt*);
     build(mid+,r,rt*+);
     pushup(rt);
 }
 int query(int be, int ed, int l, int r, int rt) {
     if (be <= l && r <= ed) {
         return sum[rt];
     }
     int mid = (l+r)/, res = ;
     if (be <= mid) res |= query(be,ed,l,mid,rt*);
     if (ed > mid) res |= query(be,ed,mid+,r,rt*+);
     return res;
 }

 struct PAM {
     int last;
     struct Node {
         ll cnt, len, fail, son[];  // cnt为以i为结尾的回文子串个数，len为长度
         Node(int len, int fail) : len(len), fail(fail), cnt(){
             memset(son, , sizeof(son));
         };
     };
     vector<Node> st;
     inline int newnode(int len, int fail = ) {
         st.emplace_back(len, fail);
         return st.size()-;
     }
     inline int getfail(int x, int n) {
         while (s[n-st[x].len-] != s[n]) x = st[x].fail;
         return x;
     }
     inline void extend(int c, int i) {
         int cur = getfail(last, i);
         if (!st[cur].son[c]) {
             int nw = newnode(st[cur].len+, st[getfail(st[cur].fail, i)].son[c]);
             st[cur].son[c] = nw;
         }
         st[ last=st[cur].son[c] ].cnt++;
         record[last] = i;
     }
     void init() {
         scanf("%s", s+);
         n = strlen(s+);
         s[] = ;
         newnode(, ), newnode(-);
         last = ;
         for (int i = ; i <= n; i++)
             extend(s[i]-'a', i);
     }
     ll count() {
         for (int i = st.size()-; i >= ; i--)
             st[st[i].fail].cnt += st[i].cnt;

         ll ans = n;
         for (int i = ; i <= st.size()-; i++) {
             if (st[i].len <= ) continue;

             int L = record[i]-st[i].len+, R = record[i];
             int res = query(L,R,,n,);
             int num = ;
             while (res) {
                 if (res&) num++;
                 res >>= ;
             }
             ans += st[i].cnt*num;
         }
         return ans;
     }
 }pam;
 int main() {
     pam.init();
     build(,n,);
     printf("%lld\n",pam.count());
     return ;
 }