主要思路：线段树
线段树大法好
我觉得这道题就是把区间修改，区间查询的普通线段树改了改懒标记就完了
不会线段树？不着急啊，我们有入门宝典——
具体线段树入门：
Blog发完就跑
记得，这里的xor如果xor两次就相当于没操作，所以我们在维护懒标记时可以再偷点懒，每次懒标记取反。
我们区间取反时，实际上是原来是0，现在变为1，原来是1，现在变为0，他们的数目是互补的，所以区间取反后1的数目就是之前0的数目
代码：
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define go(i, j, n, k) for (int i = j; i <= n; i += k)
#define fo(i, j, n, k) for (int i = j; i >= n; i -= k)
#define rep(i, x) for (int i = h[x]; i; i = e[i].nxt)
#define mn 222222
#define inf 2147483647
#define ll long long
#define ld long double
#define fi first
#define se second
#define root 1, n, 1
#define lson l, m, rt << 1
#define rson m + 1, r, rt << 1 | 1
#define bson l, r, rt
//#define LOCAL
#define mod
#define Debug(...) fprintf(stderr, __VA_ARGS__)
inline int read(){
int f = 1, x = 0;char ch = getchar();
while (ch > '9' || ch < '0'){if (ch == '-')f = -f;ch = getchar();}
while (ch >= '0' && ch <= '9'){x = x * 10 + ch - '0';ch = getchar();}
return x * f;
}
//This is AC head above...
int z[mn << 2], col[mn << 2], a[mn];
inline void update(int rt){
z[rt] = z[rt << 1] + z[rt << 1 | 1];
}
inline void color(int l,int r,int rt){
z[rt] = (r - l + 1) - z[rt];
col[rt] ^= 1;
}
inline void push_col(int l,int r,int rt){
if(col[rt]){
int m = (l + r) >> 1;
color(lson);
color(rson);
col[rt] = 0;
}
}
inline void build(int l,int r,int rt){
if(l==r){
z[rt] = a[l];
return;
}
int m = (l + r) >> 1;
build(lson);
build(rson);
update(rt);
}
inline void modify(int l,int r,int rt,int nowl,int nowr){
if(nowl<=l && r<=nowr){
col[rt] ^= 1;
z[rt] = (r - l + 1) - z[rt];
return;
}
int m = (l + r) >> 1;
push_col(bson);
if(nowl<=m)
modify(lson, nowl, nowr);
if(m<nowr)
modify(rson, nowl, nowr);
update(rt);
}
inline int query(int l,int r,int rt,int nowl,int nowr){
if(nowl<=l && r<=nowr){
return z[rt];
}
int m = (l + r) >> 1;
push_col(bson);
if(nowl<=m){
if(m<nowr)
return query(lson, nowl, nowr) + query(rson, nowl, nowr);
else
return query(lson, nowl, nowr);
}else
return query(rson, nowl, nowr);
}
int n, m;
inline void debug(){
go(i, 1, n, 1) printf("%d ", a[i]);
puts("");
}
int main(){
n = read(), m = read();
string c;
cin >> c;
go(i, 0, n - 1, 1)
a[i + 1] = c[i] - '0';
//debug();
build(root);
go(i,1,m,1){
int s = read(), x = read(), y = read();
if(!s)
modify(root, x, y);
else
cout << query(root, x, y) << "\n";
}
#ifdef LOCAL
Debug("\nMy Time: %.3lfms\n", (double)clock() / CLOCKS_PER_SEC);
#endif
return 0;
}