The 2022 ICPC Asia Nanjing Regional Contest

Author: Macesuted

QOJ/5414.cpp

@@ -0,0 +1,78 @@
+/**
+ * @file 5414.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-10-21
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+#define maxn 2005
+
+void solve(void) {
+    int n, m, k;
+    cin >> n >> m >> k;
+    string s;
+    cin >> s;
+
+    int xl = 1, xr = n, yl = 1, yr = m, dx = 0, dy = 0;
+    for (int i = 0; i < (int)s.size(); i++) {
+        if (s[i] == 'U') xl--, xr--, dx--;
+        if (s[i] == 'D') xl++, xr++, dx++;
+        if (s[i] == 'L') yl--, yr--, dy--;
+        if (s[i] == 'R') yl++, yr++, dy++;
+        if (xl < 1) xl = 1;
+        if (xr > n) xr = n;
+        if (yl < 1) yl = 1;
+        if (yr > m) yr = m;
+    }
+    xl -= dx, xr -= dx, yl -= dy, yr -= dy;
+
+    if (xl > xr || yl > yr) return cout << (k == 0 ? n * m : 0) << endl, void();
+
+    int x0 = n + 5, y0 = m + 5;
+    int x = x0, y = y0;
+    vector<vector<int>> f(x0 + n + 5, vector<int>(y0 + m + 5, 0));
+    f[x0][y0] = 1;
+    for (int i = 0; i < (int)s.size(); i++) {
+        if (s[i] == 'U') x++;
+        if (s[i] == 'D') x--;
+        if (s[i] == 'L') y++;
+        if (s[i] == 'R') y--;
+        f[x][y] = 1;
+    }
+
+    for (int i = 0; i < (int)f.size(); i++)
+        for (int j = 1; j < (int)f[0].size(); j++) f[i][j] += f[i][j - 1];
+    for (int i = 1; i < (int)f.size(); i++)
+        for (int j = 0; j < (int)f[0].size(); j++) f[i][j] += f[i - 1][j];
+
+    auto sum = [&](int xl, int xr, int yl, int yr) -> int {
+        return f[xr][yr] - f[xl - 1][yr] - f[xr][yl - 1] + f[xl - 1][yl - 1];
+    };
+
+    k = (xr - xl + 1) * (yr - yl + 1) - k;
+
+    int ans = 0;
+    for (int i = 1; i <= n; i++)
+        for (int j = 1; j <= m; j++) ans += (sum(xl - i + x0, xr - i + x0, yl - j + y0, yr - j + y0) == k);
+
+    cout << ans << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+    return 0;
+}

QOJ/5418.cpp

@@ -0,0 +1,117 @@
+/**
+ * @file 5418.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-10-21
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+#define maxn 100005
+#define maxlgn 20
+
+class STList {
+   private:
+    int f[maxlgn][maxn], lgLen[maxn];
+
+   public:
+    void build(int n, int a[]) {
+        for (int i = 2; i <= n; i++) lgLen[i] = lgLen[i >> 1] + 1;
+        for (int i = 0; i < n; i++) f[0][i] = a[i];
+        for (int t = 1; t <= lgLen[n]; t++)
+            for (int i = 0; i + (1 << t) <= n; i++) f[t][i] = min(f[t - 1][i], f[t - 1][i + (1 << (t - 1))]);
+        return;
+    }
+    int64_t getMin(int l, int r) {
+        int t = lgLen[r - l + 1];
+        return min(f[t][l], f[t][r - (1 << t) + 1]);
+    }
+} STL;
+
+int a[maxn], dep[maxn], fa[maxn][maxlgn], dfni[maxn];
+vector<vector<int>> graph, ngraph, rec;
+
+int lca(int x, int y) {
+    if (dep[x] < dep[y]) swap(x, y);
+    for (int i = maxlgn - 1; ~i; i--)
+        if (dep[fa[x][i]] >= dep[y]) x = fa[x][i];
+    if (x == y) return x;
+    for (int i = maxlgn - 1; ~i; i--)
+        if (fa[x][i] != fa[y][i]) x = fa[x][i], y = fa[y][i];
+    return fa[x][0];
+}
+
+int dfnt = 0;
+void dfs1(int p, int pre = 0) {
+    rec[dep[p] = dep[pre] + 1].push_back(p), dfni[p] = ++dfnt, fa[p][0] = pre;
+    for (int t = 1; t < maxlgn; t++) fa[p][t] = fa[fa[p][t - 1]][t - 1];
+    for (auto q : graph[p])
+        if (q != pre) dfs1(q, p);
+    return;
+}
+
+int64_t dfs2(int p, int tar) {
+    if (ngraph[p].empty()) return STL.getMin(0, tar - 1);
+    int64_t sum = 0;
+    for (auto q : ngraph[p]) sum += dfs2(q, tar);
+    return min(sum, STL.getMin(tar - dep[p], tar - 1));
+}
+
+void solve(void) {
+    int n;
+    cin >> n;
+
+    for (int i = 0; i < n; i++) cin >> a[i];
+    STL.build(n, a);
+
+    graph.clear(), graph.resize(n + 1);
+    for (int i = 1, x, y; i < n; i++) cin >> x >> y, graph[x].push_back(y), graph[y].push_back(x);
+
+    rec.clear(), rec.resize(n + 1);
+    dfnt = 0, dfs1(1);
+
+    int64_t ans = 0;
+
+    ngraph.clear(), ngraph.resize(n + 1);
+    for (int d = 1; d <= n; d++) {
+        if (rec[d].empty()) continue;
+
+        sort(rec[d].begin(), rec[d].end(), [&](int x, int y) -> bool { return dfni[x] < dfni[y]; });
+
+        vector<int> tmp;
+        stack<int> S;
+        int head = 1;
+        for (auto x : rec[d]) {
+            int t = lca(head, x);
+            while (!S.empty() && dep[S.top()] >= dep[t])
+                tmp.push_back(S.top()), ngraph[S.top()].push_back(head), head = S.top(), S.pop();
+            if (head != t) tmp.push_back(t), ngraph[t].push_back(head), head = t;
+            if (x != t) S.push(head), head = x;
+        }
+
+        while (!S.empty()) tmp.push_back(S.top()), ngraph[S.top()].push_back(head), head = S.top(), S.pop();
+
+        ans += dfs2(1, d);
+
+        for (auto x : tmp) ngraph[x].clear();
+    }
+
+    cout << ans << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+    return 0;
+}

QOJ/5420.cpp

@@ -0,0 +1,52 @@
+/**
+ * @file 5420.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-10-21
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+#define maxn 1000005
+
+using pii = pair<int, int>;
+
+int a[maxn], pre[maxn];
+
+void solve(void) {
+    int n;
+    cin >> n;
+    for (int i = 1; i <= n; i++) cin >> a[i];
+    pre[0] = 1;
+    for (int i = 1; i <= n; i++)
+        if ((pre[i] = pre[i - 1] + (a[i] >= 0 ? +1 : -1)) <= 0) return cout << -1 << endl, void();
+
+    int cnt = pre[n], sum = 1 + n - (n + 1 - pre[n]) / 2, low = pre[n];
+    pii ans = {sum, cnt};
+    for (int i = n; i; i--) {
+        low = min(low, pre[i]);
+        if (a[i] == 0) cnt -= 2, sum--, low -= 2;
+        if (low <= 0) break;
+        if ((int64_t)ans.first * cnt < (int64_t)sum * ans.second) ans = {sum, cnt};
+    }
+
+    int64_t g = gcd(ans.first, ans.second);
+    cout << ans.first / g << ' ' << ans.second / g << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+    return 0;
+}

QOJ/5422.cpp

@@ -0,0 +1,34 @@
+/**
+ * @file 5422.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-10-21
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+void solve(void) {
+    string s;
+    cin >> s;
+    vector<int> cnt(26);
+    for (auto c : s) cnt[c - 'a']++;
+    int ans = 0;
+    for (int i = 0; i < 26; i++) ans = max(ans, cnt[i]);
+    cout << s.size() - ans << endl;
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+    return 0;
+}

QOJ/5426.cpp

@@ -0,0 +1,56 @@
+/**
+ * @file 5426.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-10-21
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+#define maxn 4005
+
+using pii = pair<int, int>;
+
+pii a[maxn];
+int f[maxn];
+
+vector<int> graph[maxn];
+
+void solve(void) {
+    int n;
+    cin >> n;
+    for (int i = 1; i <= n; i++) cin >> a[i].first >> a[i].second, a[i + n] = a[i];
+
+    int s = 2;
+    while (a[s - 1].second == a[s].second) s++;
+
+    int ans = 0;
+    for (int i = s, j; i < s + n; i = j + 1) {
+        j = i;
+        while (j + 1 < s + n && a[j].second == a[j + 1].second) j++;
+        pii pl = a[i - 1], pr = a[j + 1];
+        pii dl = {pl.first - a[i].first, pl.second - a[i].second}, dr = {pr.first - a[j].first, pr.second - a[j].second};
+        if (dl.second < 0 || dr.second < 0) continue;
+        if (a[i].first > a[j].first) continue;
+        if ((int64_t)dr.first * dl.second - (int64_t)dr.second * dl.first <= 0 && i == j) continue;
+        ans++;
+    }
+
+    cout << ans << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    while (_--) solve();
+
+    return 0;
+}