按题意直接模拟即可。

AC code：

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

int main() {
    vector<int> primes;
    bool is_prime[301] = {false};
    for (int i = 2; i <= 300; ++i) {
        if (!is_prime[i]) {
            if (i != 2) {
                primes.push_back(i);
            }
            for (int j = i * i; j <= 300; j += i) {
                is_prime[j] = true;
            }
        }
    }
    int n, m;
    cin >> n >> m;
    vector<vector<int> > result;
    vector<int> path;
    function<void(int, int, int)> backtrack = [&](int k, int sum, int start) {
        if (k == n) {
            if (sum == m) {
                result.push_back(path);
            }
            return;
        }
        if (start + (n - k) > primes.size()) {
            return;
        }
        int remain = n - k;
        int min_remain = 0;
        for (int i = 0; i < remain; ++i) {
            if (start + i >= primes.size()) {
                min_remain = INT_MAX;
                break;
            }
            min_remain += primes[start + i];
        }
        if (sum + min_remain > m) {
            return;
        }
        if (sum > m) {
            return;
        }
        for (int i = start; i < primes.size(); ++i) {
            int current = primes[i];
            if (path.empty() || current > path.back()) {
                path.push_back(current);
                backtrack(k + 1, sum + current, i + 1);
                path.pop_back();
            }
        }
    };
    backtrack(0, 0, 0);
    if (result.empty()) {
        cout << "No Answer." << endl;
    } else {
        cout << result.size() << endl;
        for (const auto& combo : result) {
            for (size_t i = 0; i < combo.size(); ++i) {
                if (i > 0) {
                    cout << " ";
                }
                cout << combo[i];
            }
            cout << endl;
        }
    }
    return 0;
}

直接爆搜即可。

#include <bits/stdc++.h>
using namespace std;
const int p[64]={3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293};
int o[22],n,m;
void output()
{
    for(int i=n;i>=1;i--)
        cout<<o[i]<<' ';
    cout<<endl;
}
int dfs1(int h,int l,int s)
{
    if(s<0) return 0;
    if(l==0)
    {
        if(s==0) return 1;
        return 0;
    }
    int ans=0;
    for(int i=h+1;i<=60;i++)
        ans+=dfs1(i,l-1,s-p[i]);
    return ans;
}
void dfs2(int h,int l,int s)
{
    if(s<0) return;
    if(l==0)
    {
        if(s==0) output();
        return;
    }
    for(int i=h+1;i<=60;i++)
    {
        o[l]=p[i];
        dfs2(i,l-1,s-p[i]);
    }
}
int main()
{
    cin>>n>>m;
    int f=dfs1(-1,n,m);
    if(!f)
    {
        puts("No Answer.");
        return 0;
    }
    cout<<f<<endl;
    dfs2(-1,n,m);
    return 0;
}