結果

問題 No.2327 Inversion Sum
ユーザー 👑 potato167
提出日時 2023-05-28 13:40:06
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 25 ms / 2,000 ms
コード長 5,730 bytes
コンパイル時間 1,919 ms
コンパイル使用メモリ 202,840 KB
最終ジャッジ日時 2025-02-13 10:06:18
ジャッジサーバーID
(参考情報)
judge4 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 30
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ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=2167167167167167167;
const int INF=2100000000;
const int mod=998244353;
#define rep(i,a,b) for (ll i=a;i<b;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){assert(!a.empty());T ans=a[0]-a[0];for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}
namespace po167{
struct combination{
int upper;
long long MOD;
std::vector<long long> fact;
std::vector<long long> rev;
std::vector<long long> fact_rev;
combination(int max,long long mod):upper(max),MOD(mod),fact(max+1),rev(max+1),fact_rev(max+1){
for(long long i=0;i<=max;i++){
if(i<2){
fact[i]=1;
fact_rev[i]=1;
rev[i]=1;
continue;
}
fact[i]=(fact[i-1]*i)%mod;
rev[i]=mod-((mod/i)*rev[mod%i])%mod;
fact_rev[i]=(fact_rev[i-1]*rev[i])%mod;
}
}
long long Comb(int x,int y){
assert(upper>=x);
if (x<y||y<0||x<0) return 0;
return (((fact_rev[y]*fact_rev[x-y])%MOD)*fact[x])%MOD;
}
long long P(int x,int y){
assert(upper>=x);
if (x<y||y<0||x<0) return 0;
return (fact_rev[x-y]*fact[x])%MOD;
}
};
}
using po167::combination;
namespace po167{
template <class T,T (*op)(T,T),T(*e)()>
struct segment_tree{
int _n,size;
std::vector<T> seg;
int ceil_pow2(int a){
int b=1;
while(a>b){
b<<=1;
}
return b;
}
void update(int k){seg[k]=op(seg[k*2],seg[k*2+1]);};
segment_tree(int n) :_n(n){
size=ceil_pow2(n);
seg=std::vector<T>(size*2,e());
}
segment_tree(std::vector<T> &p) :_n((int) p.size()){
size=ceil_pow2(_n);
seg=std::vector<T>(size*2,e());
for(int i=0;i<_n;i++) seg[i+size]=p[i];
for(int i=size-1;i>0;i--) update(i);
}
void set(int ind,T val){
assert(0<=ind&&ind<_n);
ind+=size;
seg[ind]=val;
while(ind!=1){
ind>>=1;
update(ind);
}
}
void addl(int ind,T val){
set(ind,op(get(ind),val));
}
void addr(int ind,T val){
set(ind,op(val,get(ind)));
}
T get(int ind){
assert(0<=ind&&ind<_n);
return seg[ind+size];
}
T query(int l,int r){
assert(0<=l&&l<=r&&r<=_n);
T l_val=e();
T r_val=e();
l+=size,r+=size;
while(l<r){
if(l&1) l_val=op(l_val,seg[l]),l+=1;
if(r&1) r-=1,r_val=op(seg[r],r_val);
r>>=1;
l>>=1;
}
return op(l_val,r_val);
}
template <bool (*f)(T)> int max_right(int l) {
return max_right(l, [](T x) { return f(x); });
}
template <class F> int max_right(int l, F f) {
assert(0<=l&&l<=_n);
assert(f(e()));
if(f(query(l,_n))) return _n;
T val=e();
l+=size;
while(true){
while(l%2==0) l>>=1;
if(!f(op(val,seg[l]))){
while(l<size){
l*=2;
if(f(op(val,seg[l]))){
val=op(val,seg[l]);
l++;
}
}
return l-size;
}
val=op(val,seg[l]);
l++;
}
}
template <bool (*f)(T)> int min_left(int r) {
return min_left(r, [](T x) { return f(x); });
}
template <class F> int min_left(int r, F f) {
assert(0 <= r && r <= _n);
assert(f(e()));
if (r == 0) return 0;
r += size;
T sm = e();
do {
r--;
while (r > 1 && (r % 2)) r >>= 1;
if (!f(op(seg[r], sm))) {
while (r < size) {
r = (2 * r + 1);
if (f(op(seg[r], sm))) {
sm = op(seg[r], sm);
r--;
}
}
return r + 1 - size;
}
sm = op(seg[r], sm);
} while ((r & -r) != r);
return 0;
}
};
}
using po167::segment_tree;
using F= ll;
F op(F a,F b){return a+b;}
F e(){return 0;}
int target;
bool f(F x){
return (x%target==0);
}
void solve();
// oddloop
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t=1;
//cin>>t;
rep(i,0,t) solve();
}
void solve(){
ll N,M;
cin>>N>>M;
combination table(N,mod);
vector<ll> p(N+1,1),q(N,-1);
rep(i,0,M){
ll a,b;
cin>>a>>b;
a--,b--;
q[b]=a;
p[a]=0;
}
rep(i,0,N) p[i+1]+=p[i];
ll ans=((N-M)*(N-M-1))/2;
ans%=mod;
ans=(ans*table.fact_rev[2])%mod;
ll X=0,Y=N-M;
segment_tree<F,op,e> seg(N);
rep(i,0,N){
if(q[i]==-1){
X++,Y--;
continue;
}
ll B=p[q[i]],A=N-M-B;
ll tmp=(A*X)%mod;
tmp=(tmp+(B*Y))%mod;
tmp=(tmp*table.rev[N-M])%mod;
ans=(ans+tmp)%mod;
ans=(ans+seg.query(q[i],N))%mod;
seg.set(q[i],1);
}
ans=(ans*table.fact[N-M])%mod;
cout<<(ans+mod)%mod<<"\n";
}
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