「蓝桥」1130 第 23 场小白/强者赛 4-5-9

Author: gdut-yy

lanqiao/src/main/java/lq241130/LQ241130T4.cpp

@@ -0,0 +1,65 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+typedef long long ll;
+
+vector<vector<int>> adj;
+vector<int> tag;
+int ans = 1e9;
+
+// 当前节点，祖先分岔路数量，父亲id
+// 返回当前节点的子树是否全部都是
+int dfs(int r, int fx, int f) {
+ if (adj[r].size() == 1) {
+ if (tag[r]) ans = min(ans, fx);
+ return tag[r];
+ }
+ int nfx = adj[r].size() >= 3;
+ if (r == 0) nfx = adj[r].size() >= 2;
+ int tg = 1;
+ for (const auto &tox: adj[r]) {
+ if (tox == f) continue;
+ tg &= dfs(tox, fx + nfx, r);
+ }
+ if (tg) ans = min(ans, fx);
+ return tg;
+}
+
+void solve() {
+ int n;
+ cin >> n;
+
+ adj = vector<vector<int>>(n);
+ tag = vector<int>(n, 0);
+ for (int i = 0; i < n - 1; ++i) {
+ int l, r;
+ cin >> l >> r;
+ l--;
+ r--;
+ adj[l].push_back(r);
+ adj[r].push_back(l);
+ }
+ int m;
+ cin >> m;
+ for (int i = 0; i < m; ++i) {
+ int x;
+ cin >> x;
+ x--;
+ tag[x] = 1;
+ }
+ dfs(0, 0, -1);
+ cout << ans << endl;
+}
+
+signed main() {
+ ios::sync_with_stdio(false);
+ cin.tie(nullptr);
+
+ int t = 1;
+// cin >> t;
+ while (t--) solve();
+ return 0;
+}
+/*
+掩体计划【算法赛】
+ */

lanqiao/src/main/java/lq241130/LQ241130T5.cpp

@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+typedef long long ll;
+
+void solve() {
+ int n, k;
+ cin >> n >> k;
+
+ vector<int> a(n);
+ for (int i = 0; i < n; ++i) {
+ cin >> a[i];
+ }
+ int ans = 1;
+ for (int i = 0; i <= k; ++i) {
+ int x = a[i];
+ for (int j = 1; j * j <= x; ++j) {
+ if (x % j == 0) {
+ vector<int> b = {j, x / j};
+ for (int d: b) {
+ int cnt = 0;
+ for (int p = 0; p < n; ++p) {
+ cnt += (a[p] % d == 0);
+ }
+ if (cnt >= n - k) {
+ ans = max(ans, d);
+ }
+ }
+ }
+ }
+ }
+ cout << ans << endl;
+}
+
+signed main() {
+ ios::sync_with_stdio(false);
+ cin.tie(nullptr);
+
+ int t = 1;
+// cin >> t;
+ while (t--) solve();
+ return 0;
+}
+/*
+智商检测【算法赛】
+ */

lanqiao/src/main/java/lq241130/LQ241130T9.cpp

@@ -0,0 +1,169 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+typedef long long ll;
+
+vector<int> pre;
+const int N = 1e5 + 10;
+
+char str[N << 1];
+int w, sa[N], rk[N << 1], oldrk[N << 1];
+vector<int> height(N * 2, 0);
+
+void getsa(string s) {
+// int i, p;
+ int n = s.size();
+ for (int i = 0; i < n; ++i) {
+ str[i + 1] = s[i];
+ }
+ for (int i = 1; i <= n; ++i) {
+ sa[i] = i;
+ rk[i] = str[i];
+ }
+
+ for (w = 1; w < n; w <<= 1) {
+ sort(sa + 1, sa + n + 1, [](int x, int y) {
+ return rk[x] == rk[y] ? rk[x + w] < rk[y + w] : rk[x] < rk[y];
+ });
+ memcpy(oldrk, rk, sizeof(rk));
+ for (int p = 0, i = 1; i <= n; ++i) {
+ if (oldrk[sa[i]] == oldrk[sa[i - 1]] &&
+ oldrk[sa[i] + w] == oldrk[sa[i - 1] + w]) {
+ rk[sa[i]] = p;
+ } else {
+ rk[sa[i]] = ++p;
+ }
+ }
+ }
+ if (n == 1) rk[1] = 1;
+
+ // 处理 height 数组
+ for (int i = 1, k = 0; i <= n; ++i) {
+ if (rk[i] == 0) continue;
+ if (k) --k;
+ while (str[i + k] == str[sa[rk[i] - 1] + k]) ++k;
+ height[rk[i]] = k;
+ }
+
+ for (int i = 0; i < n; ++i) sa[i] = sa[i + 1] - 1;
+ for (int i = 0; i < n; ++i) rk[i] = rk[i + 1] - 1;
+ if (n == 1) rk[0] = 0;
+ for (int i = 0; i < n; ++i) height[i] = height[i + 1];
+}
+
+template<typename T>
+class SparseTable {
+ using VT = vector<T>;
+ using VVT = vector<VT>;
+ using func_type = function<T(const T &, const T &)>;
+
+ VVT ST;
+
+ static T default_func(const T &t1, const T &t2) { return min(t1, t2); }
+
+ func_type op;
+
+public:
+ SparseTable(const vector<T> &v, func_type _func = default_func) {
+ op = _func;
+ int len = v.size(), l1 = ceil(log2(len)) + 1;
+ ST.assign(len, VT(l1, 0));
+ for (int i = 0; i < len; ++i) {
+ ST[i][0] = v[i];
+ }
+ for (int j = 1; j < l1; ++j) {
+ int pj = 1 << (j - 1);
+ for (int i = 0; i + pj < len; ++i) {
+ ST[i][j] = op(ST[i][j - 1], ST[i + pj][j - 1]);
+ }
+ }
+ }
+
+ T query(int l, int r) {
+ int lt = r - l + 1;
+ int q = floor(log2(lt));
+ return op(ST[l][q], ST[r - (1 << q) + 1][q]);
+ }
+};
+
+int pre_sum(vector<int> &pre, int l, int r) {
+ if (l) return pre[r] - pre[l - 1];
+ return pre[r];
+}
+
+void solve() {
+ int n, q;
+ cin >> n >> q;
+
+ string s;
+ cin >> s;
+ pre = vector<int>(n, s[0] == '1');
+ for (int i = 1; i < n; ++i) {
+ pre[i] = pre[i - 1] + (s[i] - '0');
+ }
+ getsa(s);
+ SparseTable<int> st(height);
+
+ while (q--) {
+ int p, l, r;
+ cin >> p >> l >> r;
+ p--;
+ l--;
+ r--;
+
+ int lp = rk[p], rp = n;
+ // 找 [p:l] 的左右端点
+ int len = l - p + 1;
+ while (lp + 1 != rp) {
+ int mp = (lp + rp) >> 1;
+ int lcp = 0;
+ if (sa[mp] + len - 1 >= n) {
+ rp = mp;
+ continue;
+ }
+ lcp = st.query(rk[p] + 1, mp);
+ if (lcp >= len) lp = mp;
+ else rp = mp;
+ }
+ int R = lp;
+
+ lp = -1, rp = rk[p];
+ len = l - p + 1;
+ while (lp + 1 != rp) {
+ int mp = (lp + rp) >> 1;
+ int lcp = 0;
+ if (sa[mp] + len - 1 >= n) {
+ lp = mp;
+ continue;
+ }
+ lcp = st.query(mp + 1, rk[p]);
+ if (lcp >= len) rp = mp;
+ else lp = mp;
+ }
+ int L = rp;
+
+ lp = L, rp = R;
+ ll ans = 0;
+ for (int j = l; j <= r; ++j) {
+ int len = j - p + 1;
+ while (lp < n && sa[lp] + len - 1 > n || s[sa[lp] + len - 1] != s[j]) { lp++; }
+ while (rp < n && sa[rp] + len - 1 > n || s[sa[rp] + len - 1] != s[j]) { rp--; }
+ if (lp > rp) break;
+ ans += (rp - lp + 1) * pre_sum(pre, p, j);
+ }
+ cout << ans << endl;
+ }
+}
+
+signed main() {
+ ios::sync_with_stdio(false);
+ cin.tie(nullptr);
+
+ int t = 1;
+// cin >> t;
+ while (t--) solve();
+ return 0;
+}
+/*
+降维打击【算法赛】
+ */