1 #include <cstdio>
2 #include <cstdlib>
3 #include <iostream>
4 #include <algorithm>
5 #include <vector>
6
7 using namespace std;
8
9 typedef unsigned long long ull;
10 const int x = 123;
11 const int maxn = 4e5 + 10;
12
13 ull xp[maxn];
14 int n, m;
15 struct Node {
16 Node* ch[2];
17 int r, v, s;
18 int val;
19 ull Hush[2];
20 int flip;
21 Node(int v1, int v2): v(v1), val(v2) {
22 r = rand();
23 s = 1;
24 ch[0] = ch[1] = NULL;
25 flip = 0;
26 Hush[0] = Hush[1] = val;
27 }
28 bool cmp(const int &x) const {
29 if(x == v) return -1;
30 return x < v ? 0 : 1;
31 }
32 void maintain() {
33 s = 1;
34 Hush[0] = Hush[1] = val;
35 if(ch[0] != NULL) s += ch[0]->s, Hush[0] = ch[0]->Hush[ch[0]->flip] + val*xp[ch[0]->s];
36 if(ch[1] != NULL) Hush[0] += (ch[1]->Hush[ch[1]->flip])*xp[s], s += ch[1]->s;
37 int s2 = 1;
38 if(ch[1] != NULL) s2 += ch[1]->s, Hush[1] = ch[1]->Hush[(ch[1]->flip)^1] + val*xp[ch[1]->s];
39 if(ch[0] != NULL) Hush[1] += (ch[0]->Hush[(ch[0]->flip)^1])*xp[s2];
40 }
41 void pushdown() {
42 if(flip) {
43 flip = 0;
44 swap(ch[0], ch[1]);
45 if(ch[0] != NULL) ch[0]->flip = !ch[0]->flip;
46 if(ch[1] != NULL) ch[1]->flip = !ch[1]->flip;
47 }
48 }
49 };
50
51 void rotate(Node* &o, int d) {
52 Node* k = o->ch[d^1]; o->ch[d^1] = k->ch[d]; k->ch[d] = o;
53 o->maintain(); k->maintain(); o = k;
54 }
55
56 void insert(Node* &o, int x, int val) {
57 if(o == NULL) o = new Node(x, val);
58 else {
59 int d = o->cmp(x);
60 insert(o->ch[d], x, val);
61 if(o->ch[d]->r > o->r) rotate(o, d^1);
62 }
63 o->maintain();
64 }
65 void splay(Node* &o, int k) {
66 o->pushdown();
67 int s = o->ch[0] == NULL ? 0 : o->ch[0]->s;
68 int d = k <= s ? 0 : (k == s+1? -1 : 1);
69 if(d == 1) k -= s+1;
70 if(d != -1) {
71 splay(o->ch[d], k);
72 rotate(o, d^1);
73 }
74 }
75
76 Node * merge(Node* left, Node* right) {
77 splay(left, left->s);
78 left->ch[1] = right;
79 left->maintain();
80 return left;
81 }
82 void split(Node* o, int k , Node* &left, Node* &right) {
83 splay(o, k);
84 left = o;
85 right = o->ch[1];
86 o->ch[1] = NULL;
87 left->maintain();
88 }
89
90 void oper1(Node* &o, int p, int c) {
91 Node* left, *right;
92 Node* node = new Node(p+1, c);
93 split(o, p+1, left, right);
94 o = merge(merge(left, node), right);
95 }
96 void oper2(Node* &o, int p) {
97 Node* left, *mid, *right;
98 split(o, p, left, mid);
99 split(mid, 1, mid, right);
100 o = merge(left, right);
101 }
102 void oper3(Node* &o, int p1, int p2) {
103 Node *left, *mid, *right;
104 split(o, p1, left, mid);
105 split(mid, p2-p1+1, mid, right);
106 mid->flip ^= 1;
107 o = merge(merge(left, mid), right);
108 }
109 ull Hush_val(Node* &o, int p, int L) {
110 Node *left, *mid, *right;
111 split(o, p, left, mid);
112 split(mid, L, mid, right);
113 ull ans = mid->Hush[mid->flip];
114 o = merge(merge(left, mid), right);
115 return ans;
116 }
117 int oper4(Node* &o, int p1, int p2) {
118 int L = 0, R = min(n-p1+1, n-p2+1);
119 while(L < R) {
120 int M = R - (R-L)/2;
121 int l1 = Hush_val(o, p1, M), l2 = Hush_val(o, p2, M);
122 if(l1 == l2) L = M;
123 else R = M-1;
124 }
125 return L;
126 }
127 char s[maxn];
128 int main() {
129 xp[0] = 1;
130 for(int i = 1; i < maxn; i++) xp[i] = xp[i-1]*x;
131 while(scanf("%d%d", &n, &m) == 2) {
132 scanf("%s", s);
133 Node* root = new Node(0, 0);
134 for(int i = 0; i < n; i++) {
135 int c = s[i] - '0';
136 insert(root, i+1, c);
137 }
138 for(int i = 0; i < m; i++) {
139 int id, p1, p2;
140 scanf("%d", &id);
141 if(id == 1) {
142 scanf("%d%d", &p1, &p2);
143 oper1(root, p1, p2);
144 n++;
145 }
146 if(id == 2) {
147 scanf("%d", &p1);
148 oper2(root, p1);
149 n--;
150 }
151 if(id == 3) {
152 scanf("%d%d", &p1, &p2);
153 oper3(root, p1, p2);
154 }
155 if(id == 4) {
156 scanf("%d%d", &p1, &p2);
157 int ans = oper4(root, p1, p2);
158 printf("%d\n", ans);
159 }
160 }
161 }
162 return 0;
163 }
