A bunch new problems

Codeforces Round 1083 (Div. 2)/D. Simons and Beating Peaks.cpp

@@ -0,0 +1,172 @@
+/* Problem URL: https://codeforces.com/contest/2205/problem/D */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#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;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+    vi p(n);
+    cin >> p;
+
+    vi pos(n);
+    rep(i, n) {
+        pos[p[i] - 1] = i;
+    }
+
+    vi lf(n, -1);
+    vi rg(n, n);
+
+    stack<pair<int, int>> s;
+    rep(i, n) {
+        while (!s.empty() && s.top().first < p[i]) {
+            s.pop();
+        }
+
+        if (!s.empty()) {
+            lf[i] = s.top().second;
+        }
+
+        s.emplace(p[i], i);
+    }
+
+    while (!s.empty()) {
+        s.pop();
+    }
+
+    for (int i = n - 1; i >= 0; i--) {
+        while (!s.empty() && s.top().first < p[i]) {
+            s.pop();
+        }
+
+        if (!s.empty()) {
+            rg[i] = s.top().second;
+        }
+
+        s.emplace(p[i], i);
+    }
+
+    vvi dp(n, vi(2));
+
+    int ans = oo;
+    
+    for (int i = n - 1; i >= 0; i--) {
+        int ps = pos[i];
+
+        if (lf[ps] == -1) {
+            dp[i][0] = ps;
+        } else {
+            int dis = ps - lf[ps] - 1;
+            dp[i][0] = dis + dp[p[lf[ps]] - 1][0];
+        }
+
+        if (rg[ps] == n) {
+            dp[i][1] = n - ps - 1;
+        } else {
+            int dis = rg[ps] - ps - 1;
+            dp[i][1] = dis + dp[p[rg[ps]] - 1][1];
+        }
+
+        rmin(ans, dp[i][0] + dp[i][1]);
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}