Need help with a dfs simple problem !!

№	Пользователь	Рейтинг
1	tourist	4009
2	jiangly	3823
3	Benq	3738
4	Radewoosh	3633
5	jqdai0815	3620
6	orzdevinwang	3529
7	ecnerwala	3446
8	Um_nik	3396
9	ksun48	3390
10	gamegame	3386

№	Пользователь	Вклад
1	cry	167
2	Um_nik	163
3	maomao90	162
3	atcoder_official	162
5	adamant	159
6	-is-this-fft-	158
7	awoo	157
8	TheScrasse	154
9	Dominater069	153
9	nor	153

This is the problem I want to discuss : 1661B - Getting Zero

I have this answer, It's not mine but I made it cleaner (I think).

The answer

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

int main() {
 
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int M = 32768;
    vector<int> ans(M, -1);
    ans[0] = 0;

    function<int(int)> dfs = [&](int x) {
        if(ans[x] != -1) return ans[x];
        ans[x] = 1 + dfs(2 * x % M);
        ans[x] = min(ans[x], 1 + dfs((x + 1) % M));
        return ans[x];
    };
 
    int T; cin >> T;
    while (T--) {
        int n; cin >> n;
        cout << dfs(n) << "\n";
    }
    return 0;
}

I have two questions and thank you in advance.

1) Why deleting this line : return ans[x]; gives wrong answer.

2) why changing the code into the 2 code below gives wrong answer :

2 code

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

int main() {
 
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int M = 32768;
    vector<int> ans(M, -1);
    ans[0] = 0;

    function<int(int)> dfs = [&](int x) {
        if(ans[x] != -1) return ans[x];

        ans[x] = min(1 + dfs(2 * x % M), 1 + dfs((x + 1) % M));
        
        return ans[x];
    };
 
    int T; cin >> T;
    while (T--) {
        int n; cin >> n;
        cout << dfs(n) << "\n";
    }
    return 0;
}

	Rev.	Язык	Кто	Когда	Δ	Комментарий
	en1		rezidentura	2022-09-17 20:23:31	1533	Initial revision (published)

Rev.

Язык

Кто

Когда

Комментарий

en1

rezidentura

2022-09-17 20:23:31

1533

Initial revision (published)

История