codeforces 1169 D. Good Triple

题意：有长为n的串，其中有几个[ll,rr]符合条件。

首先，长度超过9的串一定符合条件。枚举左端点ll，右端点控制在ll+8就行，剩下的直接加。

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cstring>
#include <map>
#include <queue>
#include <set>
#include <cassert>
#include <stack>
#include <bitset>
#define mkp make_pair
#define err cout<<"err"<<endl
using namespace std;
const double EPS=1e-8;
typedef long long lon;
typedef unsigned long long ull;
typedef pair<int,int> pii;
const lon SZ=300010,SSZ=SZ*SZ,APB=4,one=1;
const lon INF=0x3f3f3f3f,mod=1000000007;
lon n;
char ch[SZ];

void init()
{
    cin>>ch+1;
    n=strlen(ch+1);
    lon res=0;
    for(lon i=1;i<=n;++i)
    {
        if(n>=i+8)
        {
            res+=n-(i+8)+1;
        }
        bool ok=0;
        for(lon p=i+1;p<=min(n,i+7)&&!ok;++p)
        {
            for(int k=p-1;k>=i&&!ok;--k)
            {
                lon j=k-(p-k);
                if(j>=i&&ch[j]==ch[k]&&ch[k]==ch[p])
                {
                    lon tmp=min(n,i+7)-p+1;
                    //cout<<"i: "<<i<<" "<<tmp<<endl;
                    res+=tmp;
                    ok=1;
                    break;
                }
            }
        }
    }
    cout<<res<<endl;
}

void work()
{
    
}

void release()
{
    
}

int main()
{
    std::ios::sync_with_stdio(0);
    //freopen("d:\\1.txt","r",stdin);
    lon casenum;
    //cin>>casenum;
    //cout<<casenum<<endl;
    //for(lon tim=1;tim<=casenum;++tim)
    //for(lon tim=1;cin>>n;++tim)
    {
        //cout<<"Case #"<<tim<<": ";
        init();
        work();
        release();
    }
    return 0;
}