#include <bits/stdc++.h> #define PB push_back #define ST first #define ND second //#pragma GCC optimize ("O3") //#pragma GCC target("tune=native") //mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); //#include <ext/pb_ds/assoc_container.hpp> //#include <ext/pb_ds/tree_policy.hpp> //using namespace __gnu_pbds; //typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; using namespace std; using ll = long long; using pi = pair<int, int>; using vi = vector<int>; const int nax = 1e6 + 10, INF = 1e9; int n, a[nax]; int inv[nax]; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cin >> n; for(int i = 1; i <= n; ++i) { cin >> a[i]; inv[a[i]] = i; } ll ans = 0; int l = INF, r = -INF; int ptr = 0; for(int len = 1; len <= n; ++len) { while(ptr < len/2 + 1) { l = min(l, inv[n - ptr]); r = max(r, inv[n - ptr]); ptr++; } if(r - l + 1 <= len) { int start = max(1, r - len + 1); int ed = min(n - len + 1, l); ans += ed - start + 1; } } cout << 2*n+1 << " " << ans; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | #include <bits/stdc++.h> #define PB push_back #define ST first #define ND second //#pragma GCC optimize ("O3") //#pragma GCC target("tune=native") //mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); //#include <ext/pb_ds/assoc_container.hpp> //#include <ext/pb_ds/tree_policy.hpp> //using namespace __gnu_pbds; //typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; using namespace std; using ll = long long; using pi = pair<int, int>; using vi = vector<int>; const int nax = 1e6 + 10, INF = 1e9; int n, a[nax]; int inv[nax]; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cin >> n; for(int i = 1; i <= n; ++i) { cin >> a[i]; inv[a[i]] = i; } ll ans = 0; int l = INF, r = -INF; int ptr = 0; for(int len = 1; len <= n; ++len) { while(ptr < len/2 + 1) { l = min(l, inv[n - ptr]); r = max(r, inv[n - ptr]); ptr++; } if(r - l + 1 <= len) { int start = max(1, r - len + 1); int ed = min(n - len + 1, l); ans += ed - start + 1; } } cout << 2*n+1 << " " << ans; } |