```cpp #include <iostream> #include <set> #include <functional> #include <string> using namespace std; int main() { int jv = 2; int dian = 0; // 店 int hua = 0; // 花 set<string> res; // 使用 out 或者 set.size( ) 计数都可以 string s; int out; function<void()> dfs = [&]() { if (jv < 0 || dian > 5 || hua > 10) return; if (jv == 0 && dian == 5 && hua == 10 && s[s.size() - 1] == 'b') { res.insert(s); ++out; cout << s << '\n'; return; } s += 'a'; ++dian; jv *= 2; dfs(); --dian; jv /= 2; s.pop_back(); s += 'b'; ++hua; --jv; dfs(); --hua; ++jv; s.pop_back(); }; dfs(); cout << res.size() << ' ' << out; return 0; } ```

``` #include <iostream> #include <cstring> #include <algorithm> using namespace std; const int N = 110, MOD = 1000000007; int f[N][N][N]; int n, m; int main() { cin >> n >> m; f[0][0][2] = 1; for (int i = 0; i <= n; i ++ ) for (int j = 0; j <= m; j ++ ) for (int k = 0; k <= m; k ++ ) { int& v = f[i][j][k]; if(i>=1 && k%2==0) v = (v + f[i - 1][j][k/2])%MOD; if(j>=1) v = (v + f[i][j - 1][k + 1])%MOD; } cout << f[n][m - 1][1]; return 0; } ```

随便写的，答案正确了，不知道对不对 ``` public class Main { public static void main(String[] args) { // 从结尾出发 // 最后一次是喝酒(b) int res = sum(0, 1, 1); System.out.println(res); } /** * * @param a 遇店次数 * @param b 遇花次数 * @param res 酒壶剩余酒量 * @return */ static int sum(int a, int b, int rest) { if (a == 5 && b == 10 && rest == 2) {// 终止条件 return 1; } int ans = 0; if (a + 1 <= 5 && rest % 2 == 0) { // 买酒 ans += sum(a + 1, b, rest / 2); } if (b + 1 <= 10) { //喝酒 ans += sum(a, b + 1, rest + 1); } return ans; } } ```

```Java static Set<String> ans = new HashSet<>(); public static void main(String[] args) throws IOException { solution("", 2, 0, 0); System.out.println(ans.size()); } static void solution(String path, int booze, int store, int flower) { if (booze == 0 && flower == 10 && store ==5) { ans.add(path); } else if (booze <= 0 || flower > 10 || store > 5) { } else { solution(path + "b", booze - 1, store, flower + 1); solution(path + "a", booze * 2, store + 1, flower); } } ```

``` #include <iostream> using namespace std; int res; void dfs(int d,int h,int j) { if(d==5 && h==10 && j==0) { res++; return; } if(j==0) return; if(d<5) dfs(d+1,h,j*2); if(h<10) dfs(d,h+1,j-1); } int main() { dfs(0,0,2); cout<<res; return 0; } ```

``` #include<iostream> #include<cstring> #include<algorithm> using namespace std; #define N 20 char path[N]; int numa,numb,sum,cnt; void dfs(int u) { if(u==14) { numa=0;numb=0;sum=2; for(int i=0;i<14;i++) { if(path[i]=='a') { numa++; sum*=2; } else { numb++; sum--; } } if(sum==1&&numa==5&&numb==9) { for(int i=0;i<14;i++)cout<<path[i]; cout<<endl; cnt++; } return ; } path[u]='a'; dfs(u+1); path[u]='b'; dfs(u+1); } int main() { dfs(0); cout<<cnt<<endl; return 0; } ```