7 more

CSES - CSES Problem Set/Bit_Strings.cpp

@@ -0,0 +1,19 @@
+//  Bit Strings
+
+#include<bits/stdc++.h>
+
+using namespace std;
+using ll = long long;
+ll MOD = 1e9 + 7;
+
+int main() {
+    int n; cin >> n;
+    ll ans = 1;
+    for (int i{}; i < n; i++) {
+        ans *= 2;
+        ans %= MOD;
+    }
+    ans %= MOD;
+    cout << ans;
+    return 0;
+}

CSES - CSES Problem Set/Coin_Piles.cpp

@@ -0,0 +1,23 @@
+//  Coin Piles
+
+#include<bits/stdc++.h>
+
+using namespace std;
+using ll = long long;
+
+int main() {
+    int t; cin >> t;
+    for (int T{}; T < t; T++) {
+        ll a, b; cin >> a >> b;
+        if (a < b) swap(a, b);
+        if ((a + b) % 3 != 0) {
+            cout << "NO" << endl;
+            continue;
+        } else if (a > 2*b) {
+            cout << "NO" << endl;
+            continue;
+        }
+        cout << "YES" << endl;
+    }
+    return 0;
+}

CSES - CSES Problem Set/Gray_Code.cpp

@@ -0,0 +1,32 @@
+//  Gray Code
+
+#include<bits/stdc++.h>
+
+using namespace std;
+
+vector<string> gray_code(int size, bool print) {
+    if (size == 1) {
+        if (print) {
+            cout << "0" << '\n' << "1" << endl;
+        }
+        return {"0", "1"};
+    }
+    auto prev_gray_code = gray_code(size - 1, false);
+    vector<string> output;
+    for (auto &s: prev_gray_code) {
+        if (print) cout << "0"+s << endl;
+        output.push_back("0"+s);
+    }
+    std::reverse(prev_gray_code.begin(), prev_gray_code.end());
+    for (auto &s: prev_gray_code) {
+        if (print) cout << "1"+s << endl;
+        output.push_back("1"+s);
+    }
+    return output;
+}
+
+int main() {
+    int n; cin >> n;
+    gray_code(n, true);
+    return 0;
+}

CSES - CSES Problem Set/Palindrome_Reorder.cpp

@@ -0,0 +1,31 @@
+//  Palindrome Reorder
+
+#include<bits/stdc++.h>
+
+using namespace std;
+
+int main() {
+    map<char, int> char_to_count;
+    string s; cin >> s;
+    for (auto c: s) char_to_count[c]++;
+    string forward;
+    char middle = ' ';
+    for (auto &[ch, c]: char_to_count) {
+        if (c & 1) {
+            if (middle != ' ') {
+                cout << "NO SOLUTION" << endl;
+                return 0;
+            }
+            middle = ch;
+            forward.append(string((c - 1) / 2, ch));
+        } else {
+            forward.append(string(c/2, ch));
+        }
+    }
+
+    cout << forward;
+    if (middle != ' ') cout << middle;
+    std::reverse(forward.begin(), forward.end());
+    cout << forward << endl;
+    return 0;
+}

CSES - CSES Problem Set/Tower_of_Hanoi.cpp

@@ -0,0 +1,38 @@
+//  Tower of Hanoi
+
+#include <bits/stdc++.h>
+using namespace std;
+
+void hanoi(deque<int> &current, deque<int> &destination, deque<int> &tmp, int n, vector<pair<int, int>> &remember, tuple<int, int, int> stack_names) {
+    if (n == 1) {
+        auto top = current.back();
+        current.pop_back();
+        destination.push_back(top);
+        remember.push_back({get<0>(stack_names), get<1>(stack_names)});
+        return;
+    }
+    hanoi(current, tmp, destination, n - 1, remember, {get<0>(stack_names), get<2>(stack_names), get<1>(stack_names)});
+    auto top = current.back();
+    current.pop_back();
+    destination.push_back(top);
+    remember.push_back({get<0>(stack_names), get<1>(stack_names)});
+    hanoi(tmp, destination, current, n - 1, remember, {get<2>(stack_names), get<1>(stack_names), get<0>(stack_names)});
+    return ;
+};
+
+int main() {
+    int size;
+    cin >> size;
+    deque<int> start;
+    deque<int> s2;
+    deque<int> s3;
+    for (int i = size; i > 0; i--) {
+        start.push_front(i);
+    }
+    vector<pair<int, int>> r;                                                                       //c, t, d
+    hanoi(start, s2, s3, size, r, {1, 3, 2});
+    cout << r.size() << endl;
+    for (auto &[a, b]: r) cout << a << " " << b << endl;
+    cout << endl;
+    return 0;
+}

CSES - CSES Problem Set/Trailing_Zeros.cpp

@@ -0,0 +1,16 @@
+//  Trailing Zeros
+
+#include<bits/stdc++.h>
+
+using namespace std;
+using ll = long long;
+
+int main() {
+    int count = 0;
+    ll n; cin >> n;
+    for (int i = 1; i <= 15; i++) {
+        count += n / pow(5, i);
+    }
+    cout << count;
+    return 0;
+}

CSES - CSES Problem Set/Two_Sets.cpp

@@ -0,0 +1,28 @@
+//  Two Sets
+
+#include<bits/stdc++.h>
+
+using namespace std;
+using ll = long long;
+
+int main() {
+    ll n; cin >> n;
+    if ((n * (n+1) / 2) & 1) {
+        cout << "NO" << endl;
+        return 0;
+    }
+    cout << "YES" << endl;
+    ll target_sum = n * (n+1) / 4;
+    vector<ll> first;
+    vector<ll> second;
+    for (ll i = n; i > 0; i--) {
+        if (i <= target_sum) {first.push_back(i); target_sum -= i;}
+        else second.push_back(i);
+    }
+    cout << first.size() << endl;
+    for (auto e : first) cout << e << " ";
+    cout << '\n' << second.size() << '\n';
+    for (auto e: second) cout << e << " ";
+    cout << endl;
+    return 0;
+}