Ositus

input/code.cpp: In function 'int main()':
input/code.cpp:21:17: warning: array subscript has type 'char' [-Wchar-subscripts]
    if (seen[s[j]]) break;
                 ^
input/code.cpp:22:13: warning: array subscript has type 'char' [-Wchar-subscripts]
    seen[s[j]] = 1;
             ^

#include <iostream>
using namespace std;

const int P = 1e9 + 7;
const int N = 1e6;

int dp[N + 1];

int main() {
	string s;
	cin >> s;

	int n = (int) s.size();

	dp[0] = 1;

	for (int i = 0; i < n; ++i) {
		bool seen[256] {};

		for (int j = i; j < n; ++j) {
			if (seen[s[j]]) break;
			seen[s[j]] = 1;
			dp[j + 1] += dp[i];
			dp[j + 1] %= P;
		}
	}

	cout << dp[n] << endl;
}

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