[Bzoj1014][JSOI2008]火星人prefix(无旋Treap&hash)

题目链接：https://www.lydsy.com/JudgeOnline/problem.php?id=1014

因为涉及到增加和修改，所以后缀数组就被pass掉了，想到的就是平衡树维护hash值，查询的时候就是二分相同的长度来比较，修改就是删除再增加。

这里使用的是无旋Treap

 #include<bits/stdc++.h>
 using namespace std;
 typedef long long ll;
 typedef unsigned int ull;
 const int maxn = ;
 int Siz[maxn], ls[maxn], rs[maxn], pos[maxn], val[maxn], root, cnt;
 ull Hash[maxn], w[maxn];
 inline void up(int x) {
     Siz[x] = Siz[ls[x]] + Siz[rs[x]] + ;
     w[x] = w[ls[x]] * Hash[Siz[rs[x]] + ] + Hash[Siz[rs[x]]] * val[x] + w[rs[x]];
 }
 inline void split_size(int x, int siz, int &A, int &B) {
     if (x == )return (void)(A = B = );
     if (siz <= Siz[ls[x]])
         B = x, split_size(ls[x], siz, A, ls[x]);
     else
         A = x, split_size(rs[x], siz - Siz[ls[x]] - , rs[x], B);
     up(x);
 }
 inline int Merge(int A, int B) {
     if (A ==  || B == )return A | B;
     int ans;
     if (pos[A] > pos[B])ans = A, rs[A] = Merge(rs[A], B);
     else ans = B, ls[B] = Merge(A, ls[B]);
     up(ans);
     return ans;
 }
 inline void insert(int x, char v) {
     int A, B;
     split_size(root, x, A, B);
     cnt++;
     w[cnt] = val[cnt] = v - 'a' + ;
     Siz[cnt] = ;
     pos[cnt] = rand();
     root = Merge(Merge(A, cnt), B);
 }
 inline void Delete(int x) {
     int A, B, C, D;
     split_size(root, x, A, B);
     split_size(A, x - , C, D);
     D = Merge(ls[D], rs[D]);
     root = Merge(Merge(C, D), B);
 }
 inline ull query(int l, int r) {
     int A, B, C, D;
     ull ans;
     split_size(root, l - , A, B);
     split_size(B, r - l + , C, D);
     ans = w[C];
     root = Merge(A, Merge(C, D));
     return ans;
 }
 inline bool check(int x, int y, int len) {
     return query(x, x + len - ) == query(y, y + len - );
 }
 inline int read() {
     int x = , f = ; char c = getchar();
     for (; !isdigit(c); c = getchar()) if (c == '-') f = -;
     for (; isdigit(c); c = getchar()) x = x *  + c - ''; return x * f;
 }
 inline char cread() {
     char c = getchar();
     for (; !isalpha(c); c = getchar()); return c;
 }
 inline void reads(string& s) {
     char c = getchar();
     for (; !isalpha(c); c = getchar()); s = " ";
     for (; isalpha(c); c = getchar()) s += c;
 }
 string s;
 int main() {
     reads(s);
     int n = s.size() - , m;
     m = read();
     Hash[] = ;
     for (int i = ; i < maxn; i++)
         Hash[i] = Hash[i - ] * ;
     for (int i = ; i <= n; i++)
         insert(i, s[i]);
     while (m--) {
         char opt;
         int x, y;
         opt = cread();
         if (opt == 'Q') {
             x = read(), y = read();
             int l = , r = min(n - x, n - y) + , ans;
             while (l <= r) {
                 int mid = l + r >> ;
                 if (check(x, y, mid)) {
                     ans = mid;
                     l = mid + ;
                 }
                 else
                     r = mid - ;
             }
             printf("%d\n", ans);
         }
         else if (opt == 'R') {
             x = read(), opt = cread();
             Delete(x);
             insert(x - , opt);
         }
         else {
             x = read(), opt = cread();
             n++;
             insert(x, opt);
         }
     }
     return ;
 }