atcoder grand 31

Author: seunghyukcho

atcoder/grand/31/A.cpp

@@ -0,0 +1,37 @@
+#include <iostream>
+#include <string>
+#define MOD 1000000007
+
+using namespace std;
+
+long long ans;
+int cnt[30], n;
+string s;
+
+void dfs(int here, long long ansHere)
+{
+	if(here == 'z' - 'a' + 1)
+	{
+		ans = (ans + ansHere) % MOD;
+		return;
+	}
+
+	dfs(here + 1, ansHere);
+	if(cnt[here] > 0)
+		dfs(here + 1, (ansHere * cnt[here]) % MOD);
+
+}
+
+int main()
+{
+	cin.tie(NULL);
+	ios::sync_with_stdio(false);
+
+	cin >> n >> s;
+	for(int i = 0; i < n; i++)
+		cnt[s[i] - 'a']++;
+
+	dfs(0, 1);
+
+	cout << ans - 1 << '\n';
+}