Ositus

input/code.cpp: In function 'int main()':
input/code.cpp:14:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=1;i<=mj.size();i++){
                 ~^~~~~~~~~~~

#include <bits/stdc++.h>
using namespace std;

string mj;
int raja;
int muisti[26];
long s[1000002];

int main() {
    cin>>mj;
    s[0]=0;
    s[1]=1;
    
    for(int i=1;i<=mj.size();i++){
        raja = max(muisti[mj[i-1]-'a'], raja);
        muisti[mj[i-1]-'a']=i;
        s[i+1] = 2*s[i]-s[raja]+1000000007L;
        s[i+1] %= 1000000007L;
    }
    cout<<(s[mj.size()+1]-s[mj.size()]+1000000007L)%1000000007L;
}

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