Add a lot more of my solutions.

I don't remember which ones doesn't pass though

CSES Problem Set/Meet in the Middle.cpp

@@ -0,0 +1,150 @@
+/* Problem URL: https://cses.fi/problemset/task/1628/ */
+ 
+#include <bits/stdc++.h>
+ 
+using namespace std;
+ 
+#define V vector
+ 
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+ 
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+ 
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+ 
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+ 
+using ll = long long;
+ 
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+ 
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+ 
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+ 
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+ 
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+ 
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+ 
+    int n;
+    ll s;
+    cin >> n >> s;
+ 
+    vl fds(n);
+    cin >> fds;
+ 
+    int mid = n / 2;
+ 
+    vl count;
+ 
+    function<void(int, ll)> func1 = [&](int i, ll sum) {
+        if (sum > s) {
+            return;
+        }
+
+        if (i >= mid) {
+            count.push_back(sum);
+            return;
+        }
+
+        func1(i + 1, sum);
+        func1(i + 1, sum + fds[i]);
+    };
+ 
+    ll ans = 0;
+    vl sum;
+    vl c;
+
+    function<void(int, ll)> func2 = [&](int i, ll ss) {
+        if (ss > s) {
+            return;
+        }
+
+        if (i >= n - mid) {
+            // ans += count[s - sum];
+            auto itr = lower_bound(all(sum), s - ss);
+            if (itr == sum.end() || *itr != s - ss) {
+                return;
+            }
+            ans += c[itr - sum.begin()];
+            return;
+        }
+
+        func2(i + 1, ss);
+        func2(i + 1, ss + fds[i + mid]);
+    };
+
+    func1(0, 0);
+
+    sortv(count);
+    ll prev = count[0];
+    int co = 1;
+
+    nrep(i, 1, count.size()) {
+        if (prev == count[i]) {
+            co++;
+            continue;
+        }
+
+        sum.push_back(prev);
+        c.push_back(co);
+
+        prev = count[i];
+        co = 1;
+    }
+
+    sum.push_back(prev);
+    c.push_back(co);
+
+    func2(0, 0);
+ 
+    cout << ans << '\n';
+}