#include <bits/stdc++.h> using namespace std; #define rep(i,a,n) for (int i=a;i<n;i++) #define per(i,a,n) for (int i=n-1;i>=a;i--) #define pb push_back #define mp make_pair #define all(x) (x).begin(),(x).end() #define fi first #define se second #define SZ(x) ((int)(x).size()) typedef vector<int> VI; typedef long long ll; typedef pair<int,int> PII; typedef double db; const ll mod=1000000007; ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;} ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;} // head const int N=1010000; int n,a[N],pos[N]; ll ans=0; int main() { scanf("%d",&n); rep(i,1,n+1) { scanf("%d",a+i); pos[a[i]]=i; } int l=pos[n],r=pos[n]; for (int i=1;i<=n;i++) { if (i%2==0) l=min(l,pos[n-i/2]),r=max(r,pos[n-i/2]); int L=max(1,r-i+1),R=min(n-i+1,l); ans+=max(0,R-L+1); } printf("%d %lld\n",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 | #include <bits/stdc++.h> using namespace std; #define rep(i,a,n) for (int i=a;i<n;i++) #define per(i,a,n) for (int i=n-1;i>=a;i--) #define pb push_back #define mp make_pair #define all(x) (x).begin(),(x).end() #define fi first #define se second #define SZ(x) ((int)(x).size()) typedef vector<int> VI; typedef long long ll; typedef pair<int,int> PII; typedef double db; const ll mod=1000000007; ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;} ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;} // head const int N=1010000; int n,a[N],pos[N]; ll ans=0; int main() { scanf("%d",&n); rep(i,1,n+1) { scanf("%d",a+i); pos[a[i]]=i; } int l=pos[n],r=pos[n]; for (int i=1;i<=n;i++) { if (i%2==0) l=min(l,pos[n-i/2]),r=max(r,pos[n-i/2]); int L=max(1,r-i+1),R=min(n-i+1,l); ans+=max(0,R-L+1); } printf("%d %lld\n",2*n+1,ans); } |