940. Distinct Subsequences II

class Solution {
    public int distinctSubseqII(String s) {
        long MOD = 1_000_000_007;
        long[] dp = new long[26];        
        for (char ch : s.toCharArray()) {
            int c = ch - 'a';
            long total = 1;
            for (int i = 0; i < 26; i++) {
                total = (total + dp[i]) % MOD;
            }
            dp[c] = total;
        }
        long ans = 0;
        for (int i = 0; i < 26; i++) {
            ans = (ans + dp[i]) % MOD;
        }
        return (int) ans;
    }
}

class Solution:
    def distinctSubseqII(self, s):
        MOD = 1_000_000_007

        dp = [0] * 26

        for ch in s:
            c = ord(ch) - ord('a')

            total = 1

            for i in range(26):
                total = (total + dp[i]) % MOD

            dp[c] = total

        ans = 0

        for i in range(26):
            ans = (ans + dp[i]) % MOD

        return ans

class Solution {
public:
    int distinctSubseqII(string s) {
        long long MOD = 1'000'000'007;

        vector<long long> dp(26, 0);

        for (char ch : s) {
            int c = ch - 'a';

            long long total = 1;

            for (int i = 0; i < 26; i++) {
                total = (total + dp[i]) % MOD;
            }

            dp[c] = total;
        }

        long long ans = 0;

        for (int i = 0; i < 26; i++) {
            ans = (ans + dp[i]) % MOD;
        }

        return (int)ans;
    }
};

class Solution {
    distinctSubseqII(s) {
        const MOD = 1000000007;

        const dp = new Array(26).fill(0);

        for (const ch of s) {
            const c = ch.charCodeAt(0) - 'a'.charCodeAt(0);

            let total = 1;

            for (let i = 0; i < 26; i++) {
                total = (total + dp[i]) % MOD;
            }

            dp[c] = total;
        }

        let ans = 0;

        for (let i = 0; i < 26; i++) {
            ans = (ans + dp[i]) % MOD;
        }

        return ans;
    }
}