monk.cpp

#include<bits/stdc++.h>
#define all(a) a.begin(),a.end()
#define ll long long
#define inp(a) scanf("%d",&a)
#define out(a) printf("%d\n",a)
#define inp2(a) scanf("%lld",&a)
#define out2(a) printf("%lld\n",a)
#define arrinput(a,n) for(int i=0;i<n;i++) scanf("%d",&a[i]);
#define pii pair<int,int> 
#define piii pair<int,pair<int,int> >
#define vi vector<int>
#define rep(i,start,n) for(int i=start;i<n;i++)
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define vb vector<bool>
#define testcases() int test;scanf("%d",&test);while(test--)
#define priorityqueue priority_queue<int,vector<int>,greater<int> >
#define minheappop(a) pop_heap(a.begin(),a.end(),compare);a.pop_back();
#define maxheappop(a) pop_heap(a.begin(),a.end());a.pop_back();
#define minheappush(a,b) a.push_back(b);push_heap(a.begin(),a.end(),compare);
#define maxheappush(a,b) a.push_back(b);push_heap(a.begin(),a.end());
const int mod=1000000007;
using namespace std;
int main()
{
    int n,q,type,index,l,r;
    string s;
    char ch;
    inp(n);inp(q);
    cin>>s;
    vector< vector<int> > bit(n+1,vector<int>(26,0));
    rep(i,0,n)
    {
        index=i+1;
        while(index<=n)
        {
            bit[index][s[i]-'a']++;
            index+=(index&-index);               
        }
    }    
    while(q--)
    {
        inp(type);
        if(type==1)
        {
            cin>>l>>ch;
            if(ch!=s[l-1])
            {
                index=l;
                while(index<=n)
                {
                    bit[index][s[l-1]-'a']--;
                    bit[index][ch-'a']++;
                    index+=(index&-index);
                }
                s[l-1]=ch;
            }
        }
        else if(type==2)
        {
            inp(l);inp(r);
            vector<int> counts(26,0);
            index=r;
            while(index>0)
            {
                for(int i=0;i<26;i++)
                    counts[i]+=bit[index][i];
                index-=(index&-index);
            }
            index=l-1;
            while(index>0)
            {
                for(int i=0;i<26;i++)
                    counts[i]-=bit[index][i];
                index-=(index&-index);
            }
            int flag;
            if((r-l+1)%2)
                flag=2;
            else
                flag=1;
            int i;
            for(i=0;i<26;i++)
            {
                if(counts[i]%2)
                    flag--;
                if(!flag)
                    break;
            }
            if(i!=26)
                printf("no\n");
            else
                printf("yes\n");
        }
    }
    return 0;
}