珂朵莉树*2，开吸氧快得如同漂移
顺便读入也实在恶心，疯狂用getchar()读入的
代码：
#include <bits/stdc++.h> //#define int long long #define sc(a) scanf("%lld",&a) #define scc(a,b) scanf("%lld %lld",&a,&b) #define sccc(a,b,c) scanf("%lld %lld %lld",&a,&b,&c) #define schar(a) scanf("%c",&a) #define pr(a) printf("%lld",a) #define fo(i,a,b) for(int i=a;i<b;++i) #define re(i,a,b) for(int i=a;i<=b;++i) #define rfo(i,a,b) for(int i=a;i>b;--i) #define rre(i,a,b) for(int i=a;i>=b;--i) #define prn() printf("\n") #define prs() printf(" ") #define mkp make_pair #define pii pair<int,int> #define pub(a) push_back(a) #define pob() pop_back() #define puf(a) push_front(a) #define pof() pop_front() #define fst first #define snd second #define frt front() #define bak back() #define mem0(a) memset(a,0,sizeof(a)) #define memmx(a) memset(a,0x3f3f,sizeof(a)) #define memmn(a) memset(a,-0x3f3f,sizeof(a)) #define debug #define db double #define yyes cout<<"Yes"<<endl; #define nno cout<<"No"<<endl; using namespace std; typedef vector<int> vei; typedef vector<pii> vep; typedef map<int,int> mpii; typedef map<char,int> mpci; typedef map<string,int> mpsi; typedef deque<int> deqi; typedef deque<char> deqc; typedef priority_queue<int> mxpq; typedef priority_queue<int,vector<int>,greater<int> > mnpq; typedef priority_queue<pii> mxpqii; typedef priority_queue<pii,vector<pii>,greater<pii> > mnpqii; const int maxn=500005; //const int inf=0x3f3f3f3f3f3f3f3f; const int MOD=100000007; const db eps=1e-10; int qpow(int a,int b){int tmp=a%MOD,ans=1;while(b){if(b&1){ans*=tmp,ans%=MOD;}tmp*=tmp,tmp%=MOD,b>>=1;}return ans;} int lowbit(int x){return x&-x;} int max(int a,int b){return a>b?a:b;} int min(int a,int b){return a<b?a:b;} int mmax(int a,int b,int c){return max(a,max(b,c));} int mmin(int a,int b,int c){return min(a,min(b,c));} void mod(int &a){a+=MOD;a%=MOD;} bool chk(int now){} int half(int l,int r){while(l<=r){int m=(l+r)/2;if(chk(m))r=m-1;else l=m+1;}return l;} int ll(int p){return p<<1;} int rr(int p){return p<<1|1;} int mm(int l,int r){return (l+r)/2;} int lg(int x){if(x==0) return 1;return (int)log2(x)+1;} bool smleql(db a,db b){if(a<b||fabs(a-b)<=eps)return true;return false;} db len(db a,db b,db c,db d){return sqrt((a-c)*(a-c)+(b-d)*(b-d));} bool isp(int x){if(x==1)return false;if(x==2)return true;for(int i=2;i*i<=x;++i)if(x%i==0)return false;return true;} inline int read(){ char ch=getchar();int s=0,w=1; while(ch<48||ch>57){if(ch=='-')w=-1;ch=getchar();} while(ch>=48&&ch<=57){s=(s<<1)+(s<<3)+ch-48;ch=getchar();} return s*w; } inline void write(int x){ if(x<0)putchar('-'),x=-x; if(x>9)write(x/10); putchar(x%10+48); } int gcd(int a, int b){ if(a==0) return b; if(b==0) return a; if(!(a&1)&&!(b&1)) return gcd(a>>1,b>>1)<<1; else if(!(b&1)) return gcd(a,b>>1); else if(!(a&1)) return gcd(a>>1,b); else return gcd(abs(a-b),min(a,b)); } int lcm(int x,int y){return x*y/gcd(x,y);} int n,m; char ss[maxn]; struct node{ int l,r; char v; node(int L,int R=-1,char V='#'):l(L),r(R),v(V){} bool operator < (const node& o)const{return l<o.l;} }; set<node> s; typedef set<node>::iterator it; it split(int pos){ it i=s.lower_bound(node(pos)); if(i!=s.end()&&i->l==pos) return i; --i; int L=i->l,R=i->r; char V=i->v; s.erase(i); s.insert(node(L,pos-1,V)); return s.insert(node(pos,R,V)).fst; } void assign(int x,int y,char c){ it ir=split(y+1),il=split(x); s.erase(il,ir); s.insert(node(x,y,c)); } bool is(int x,int y){ it ir=split(y+1),il=split(x); char tmp=il->v; for(it i=il;i!=ir;++i){ if(i->v!=tmp) return 0; } if(x>=2&&y<=n-1){ il--; if(il->v==ir->v) return 0; } return 1; } signed main(){ n=read(); scanf("%s",ss+1); // re(i,1,n) s.insert(node(i,i,ss[i])); int cnt=1; char last=ss[1]; re(i,2,n){ if(ss[i]==last) ++cnt; else{ s.insert(node(i-cnt,i-1,last)); last=ss[i]; cnt=1; } } s.insert(node(n+1-cnt,n,last)); m=read(); while(m--){ char op,z; op=getchar(); while(op!='A'&&op!='B') op=getchar(); int x,y; x=read(),y=read(); if(op=='A'){ z=getchar(); while(z!='A'&&z!='B'&&z!='C') z=getchar(); assign(x,y,z); } else{ if(is(x,y)) puts("Yes"); else puts("No"); } } return 0; }