Ositus

input/code.cpp: In function 'int main()':
input/code.cpp:17:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<s.size();i++)
                 ~^~~~~~~~~

#include <bits/stdc++.h>

using namespace std;

#define M 1000000007

typedef long long int ll;

string s;
ll r,vr;
map<char,pair<int,pair<ll,ll>>> m;

int main()
{
    cin>>s;
    ll pf = -1;
    for(int i=0;i<s.size();i++)
    {
        char c = s[i];
        if(i == 0)
        {
            r=1;
        }
        else
        {
            r *= 2;
            if(m[c].first>pf && m[c].second.first > 0)
            {
                ll cvr = vr - m[c].second.second;
                cvr = cvr > 0 ? cvr : cvr+M;
                cvr = m[c].second.first - cvr;
                cvr = cvr > 0 ? cvr : cvr+M;
                r -= cvr;
                if(r<0) r += M;
                vr += cvr;
            }
            if(m[c].second.first>0) pf = pf > m[c].first ? pf : m[c].first;
        }
        r %= M;
        vr %= M;
        m[c] = make_pair(i, make_pair(r, vr));
    }
    cout<<r;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: ACCEPTED

Test 6

Group: 3

Verdict: ACCEPTED

Test 7

Group: 3

Verdict: ACCEPTED