我写了一个大常数的O(nlogn)算法在洛谷上过了，然后在usaco上交就没跑过。 算法是瞎想的因为没找到什么特别好的规律

代码是这样的：

#include<iostream>
#include<cstring>
#include<cmath>
#include<cstdio>
using namespace std;
string s;
int q;
const int maxs = 2e5+10;
int f[maxs][20]; 
int judge(int a,int b)
{
    if(b < a)
    {
        swap(a,b);
    }
    if(a == b)
    {
        return 0;
    }
    else if((a == 0 && b == 1)|| (a == 2 && b ==3))
    {
        return 1;
    }
    else if((a == 0 && b == 2)|| (a == 1 && b ==3))
    {
        return 2;
    }
    else 
        return 3;
}
void init()
{
	for(int i=0;i<s.size();i++)
	{
		if(s[i] == 'C')
		{	
			f[i+1][0] = 1;
		}
		else if(s[i] == 'O')
		{
			f[i+1][0] = 2;	
		}
        else
        {
            f[i+1][0] = 3;
        }
	}
	for(int j = 1;j<=20;j++)
	{
		for(int i=1;i<=s.size();i++)
		{
			if(i+pow(2,j)-1<=s.size())
			{
				f[i][j] = judge(f[i][j-1],f[i+(int)pow(2,j-1)][j-1]);	
			}
		}
	}
}
int proc(int x,int y)
{
    int ans = 0;
    int num = y-x+1;
    int curr = x;
    for(int i = 18;i >= 0;i--)
    {
        if(num >= (int)pow(2,i))
        {
            num = num - (int)pow(2,i);
            ans = judge(ans,f[curr][i]);
            curr = curr + (int)pow(2,i);
        }
    }
    return ans;
}
int main()
{
	getline(cin,s);
	init();
	cin>>q;
	for(int i=1;i<=q;i++)
	{
		int x,y;
		cin>>x>>y;
		int result = proc(x,y);	
		if(result == 1)
		{
			cout<<"Y";	
		}
		else
		{
			cout<<"N";	
		}
	}
	return 0;	
}