AtCoder & CodeForces solutions.

Author: mitkonikov

AtCoder/A_2_UP_3_DOWN.cpp

@@ -0,0 +1,16 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int X, Y;
+    cin >> X >> Y;
+    if ((Y > X && Y <= X + 2) || (Y < X && Y >= X - 3)) {
+        cout << "Yes" << endl;
+    } else {
+        cout << "No" << endl;
+    }
+    return 0;
+}

AtCoder/A_Arithmetic_Progression.cpp

@@ -0,0 +1,16 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int A, B, D;
+    cin >> A >> B >> D;
+    while (A <= B) {
+        cout << A << " ";
+        A += D;
+    }
+    cout << endl;
+    return 0;
+}

AtCoder/A_Capitalized.cpp

@@ -0,0 +1,17 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    string S;
+    cin >> S;
+    bool ok = true;
+    for (int i = 0; i < S.size(); i++) {
+        if (i == 0) ok &= (S[i] >= 'A' && S[i] <= 'Z');
+        else ok &= (S[i] >= 'a' && S[i] <= 'z');
+    }
+    cout << (ok ? "Yes" : "No") << endl;
+    return 0;
+}

AtCoder/A_Scoreboard.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int N;
+    cin >> N;
+    ll A = 0, B = 0;
+    for (int i = 0; i < N; i++) {
+        int x, y;
+        cin >> x >> y;
+        A += x;
+        B += y;
+    }
+    if (A == B) {
+        cout << "Draw" << endl;
+    } else if (A > B) {
+        cout << "Takahashi" << endl;
+    } else {
+        cout << "Aoki" << endl;
+    }
+    return 0;
+}

AtCoder/B_326_like_Numbers.cpp

@@ -0,0 +1,19 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int N;
+    cin >> N;
+    for (int i = N;; i++) {
+        int d1 = i / 100;
+        int d2 = i / 10 % 10;
+        if ((i % 10) == d1 * d2) {
+            cout << i << endl;
+            return 0;
+        }
+    }
+    return 0;
+}

AtCoder/B_Append.cpp

@@ -0,0 +1,21 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int Q;
+    cin >> Q;
+    vector<int> A;
+    for (int i = 0; i < Q; i++) {
+        int t, x;
+        cin >> t >> x;
+        if (t == 1) {
+            A.push_back(x);
+        } else {
+            cout << A[A.size() - x] << endl;
+        }
+    }
+    return 0;
+}

AtCoder/B_Extended_ABC.cpp

@@ -0,0 +1,18 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    string S;
+    cin >> S;
+    char expect = 'A';
+    bool ok = true;
+    for (int i = 0; i < S.size(); i++) {
+        ok &= (S[i] >= expect);
+        expect = max(expect, S[i]);
+    }
+    cout << (ok ? "Yes" : "No") << endl;
+    return 0;
+}

AtCoder/B_Frequency.cpp

@@ -0,0 +1,20 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    vector<int> frq(26);
+    string S;
+    cin >> S;
+    for (int i = 0; i < S.size(); i++) frq[S[i] - 'a']++;
+    int f = 0;
+    for (int i = 0; i < 26; i++) {
+        if (frq[i] > frq[f]) {
+            f = i;
+        }
+    }
+    cout << (char)('a' + f) << endl;
+    return 0;
+}

AtCoder/C_Divide_and_Divide.cpp

@@ -0,0 +1,26 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    ll X;
+    cin >> X;
+    map<ll, ll> mp;
+    mp[X] = 1;
+    ll cost = 0;
+    while (!mp.empty()) {
+        map<ll, ll> new_mp;
+        for (auto [v, frq]: mp) {
+            cost += v * frq;
+            ll nv1 = v / 2;
+            ll nv2 = (v + 1) / 2;
+            if (nv1 > 1) new_mp[nv1] += frq;
+            if (nv2 > 1) new_mp[nv2] += frq;
+        }
+        mp.swap(new_mp);
+    }
+    cout << cost << endl;
+    return 0;
+}

AtCoder/C_Leftover_Recipes.cpp

@@ -0,0 +1,35 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int N;
+    cin >> N;
+    vector<ll> Q(N), A(N), B(N);
+    for (int i = 0; i < N; i++) cin >> Q[i];
+    for (int i = 0; i < N; i++) cin >> A[i];
+    for (int i = 0; i < N; i++) cin >> B[i];
+    int ans = 0;
+    for (ll a = 0; a < (ll)(1e6 + 100); a++) {
+        bool failed = false;
+        for (int i = 0; i < N; i++) {
+            if (a * A[i] > Q[i]) {
+                failed = true;
+                break;
+            }
+        }
+        if (failed) break;
+        int mx = INT_MAX;
+        for (int i = 0; i < N; i++) {
+            int b_left = Q[i] - a * A[i];
+            if (B[i] == 0) continue;
+            if (b_left <= 0) mx = 0;
+            else mx = min(mx, (int)(b_left / B[i]));
+        }
+        ans = max(ans, mx + (int)a);
+    }
+    cout << ans << endl;
+    return 0;
+}

AtCoder/C_Lining_Up_2.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int N;
+    cin >> N;
+    vector<int> A(N);
+    for (int i = 0; i < N; i++) cin >> A[i];
+    vector<int> rev(N);
+    for (int i = 0; i < N; i++) {
+        if (A[i] != -1) {
+            rev[A[i]-1] = i;
+        }
+    }
+    vector<int> ans;
+    for (int i = 0; i < N; i++) {
+        if (A[i] == -1) {
+            for (int k = 0, ind = i; k < N; k++, ind = rev[ind]) {
+                ans.push_back(ind + 1);
+            }
+            break;
+        }
+    }
+    for (auto el: ans) cout << el << " ";
+    cout << endl;
+    return 0;
+}

AtCoder/C_Peak.cpp

@@ -0,0 +1,24 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+int main() {
+    int N, M;
+    cin >> N >> M;
+    vector<int> A(N);
+    for (int i = 0; i < N; i++) cin >> A[i];
+    sort(A.begin(), A.end());
+    int p = 0;
+    int ans = 0;
+    for (int i = 0; i < N; i++) {
+        while (p < A.size() && A[p] - A[i] < M) {
+            p++;
+        }
+
+        ans = max(ans, p - i);
+    }
+    cout << ans << endl;
+    return 0;
+}

AtCoder/C_Target_Practice.cpp

@@ -0,0 +1,33 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+void testCase() {
+    vector<string> A(10);
+    for (int i = 0; i < 10; i++) cin >> A[i];
+    int ans = 0;
+    for (int i = 0; i < 10; i++) {
+        for (int j = 0; j < 10; j++) {
+            if (A[i][j] == 'X') {
+                ans += (min({
+                    i, j, 9-i, 9-j
+                })) + 1;
+            }
+        }
+    }
+    cout << ans << endl;
+}
+
+int main() {
+    int t;
+    cin >> t;
+
+    while (t--) {
+        testCase();
+    }
+
+    cout << flush;
+    return 0;
+}

AtCoder/D_Cheating_Gomoku_Narabe.cpp

@@ -0,0 +1,58 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define endl '\n'
+
+using namespace std;
+
+vector<string> rotate(const vector<string>& matrix, int x, int y) {
+    vector<string> result(x, string(y, '.'));
+
+    int newColumn, newRow = 0;
+    for (int oldColumn = x - 1; oldColumn >= 0; oldColumn--) {
+        newColumn = 0;
+        for (int oldRow = 0; oldRow < y; oldRow++) {
+            result[newRow][newColumn] = matrix[oldRow][oldColumn];
+            newColumn++;
+        }
+        newRow++;
+    }
+
+    return result;
+}
+
+int main() {
+    int N, M, K;
+    cin >> N >> M >> K;
+    vector<string> A(N);
+    for (int i = 0; i < N; i++) cin >> A[i];
+    int ans = INT_MAX;
+    for (int rep: { 0, 1 }) {
+        if (K <= M) {
+            for (int i = 0; i < N; i++) {
+                int count = 0;
+                int xs = 0;
+                for (int j = 0; j < K; j++) {
+                    count += (A[i][j] == 'o');
+                    xs += (A[i][j] == 'x');
+                }
+                if (xs == 0) ans = min(ans, K - count);
+                for (int jj = K; jj < M; jj++) {
+                    count -= (A[i][jj-K] == 'o');
+                    xs -= (A[i][jj-K] == 'x');
+                    count += (A[i][jj] == 'o');
+                    xs += (A[i][jj] == 'x');
+                    if (xs == 0) ans = min(ans, K - count);
+                }
+            }
+
+            if (rep == 1) {
+                break;
+            }
+        }
+
+        A = rotate(A, M, N);
+        swap(M, N);
+    }
+    cout << (ans == INT_MAX ? -1 : ans) << endl;
+    return 0;
+}