leetcode.learning/distinct-subsequences.cpp at main · darion-yaphet/leetcode.learning · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
//
// Created by Chenguang Wang on 2024/2/25.
//

// https://leetcode.cn/problems/distinct-subsequences/description/

#include <string>
#include <vector>

using namespace std;

class Solution {
public:
    int numDistinct(string s, string t) {
        vector<vector<uint64_t>> dp(s.size() + 1, vector<uint64_t>(t.size() + 1));
        for (int i = 0; i < s.size(); i++) {
            dp[i][0] = 1;
        }

        for (int j = 1; j < t.size(); j++) {
            dp[0][j] = 0;
        }

        for (int i = 1; i <= s.size(); i++) {
            for (int j = 1; j <= t.size(); j++) {
                if (s[i - 1] == t[j - 1]) {
                    dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j];
                } else {
                    dp[i][j] = dp[i - 1][j];
                }
            }
        }
        return dp[s.size()][t.size()];
    }
};