結果
問題 | No.1115 二つの数列 / Two Sequences |
ユーザー |
|
提出日時 | 2020-07-17 22:12:26 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 40 ms / 2,000 ms |
コード長 | 2,009 bytes |
コンパイル時間 | 3,110 ms |
コンパイル使用メモリ | 197,064 KB |
最終ジャッジ日時 | 2025-01-11 22:47:14 |
ジャッジサーバーID (参考情報) |
judge3 / judge3 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 5 |
other | AC * 35 |
コンパイルメッセージ
main.cpp: In function ‘int main()’: main.cpp:87:21: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 87 | int n; scanf("%d",&n); | ~~~~~^~~~~~~~~ main.cpp:89:23: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 89 | rep(i,n) scanf("%d",&a[i]), a[i]--; | ~~~~~^~~~~~~~~~~~ main.cpp:90:23: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 90 | rep(i,n) scanf("%d",&b[i]), b[i]--; | ~~~~~^~~~~~~~~~~~
ソースコード
#include <bits/stdc++.h>#define rep(i,n) for(int i=0;i<(n);i++)using namespace std;template<class G>class Fenwick_tree{vector<G> a;public:Fenwick_tree(){}Fenwick_tree(int n){ build(n); }Fenwick_tree(const vector<G>& a){ build(a); }void build(int n){a.assign(n,G{});}void build(const vector<G>& a){this->a=a;for(int i=1;i<a.size();i++) if(i+(i&-i)-1<a.size()) (this->a)[i+(i&-i)-1]+=(this->a)[i-1];}void add(int i,const G& val){for(i++;i<=a.size();i+=i&-i) a[i-1]+=val;}G sum(int l,int r)const{if(l==0){G res{};for(;r>0;r-=r&-r) res+=a[r-1];return res;}return sum(0,r)-sum(0,l);}int lower_bound(G val)const{if(val<=G{}) return 0;int x=0,k;for(k=1;k<=a.size();k<<=1);for(k>>=1;k>0;k>>=1) if(x+k<=a.size() && a[x+k-1]<val) val-=a[x+k-1], x+=k;return x;}int upper_bound(G val)const{if(val<G{}) return 0;int x=0,k;for(k=1;k<=a.size();k<<=1);for(k>>=1;k>0;k>>=1) if(x+k<=a.size() && a[x+k-1]<=val) val-=a[x+k-1], x+=k;return x;}};class permutation{vector<int> f;public:permutation(){}permutation(int n){f.resize(n);iota(f.begin(),f.end(),0);}permutation(const vector<int>& p):f(p){}permutation operator*(const permutation& p)const{int n=f.size();permutation res(n);rep(i,n) res.f[i]=f[p[i]];return res;}int operator[](int i)const{ return f[i]; }int size()const{ return f.size(); }void swap(int i,int j){ std::swap(f[i],f[j]); }friend permutation inverse(const permutation& p){int n=p.f.size();permutation res(n);rep(i,n) res.f[p.f[i]]=i;return res;}};long long inversion_number(const permutation& p){int n=p.size();long long res=0;Fenwick_tree<int> F(n);rep(i,n){ res+=F.sum(p[i]+1,n); F.add(p[i],1); }return res;}int main(){int n; scanf("%d",&n);vector<int> a(n),b(n);rep(i,n) scanf("%d",&a[i]), a[i]--;rep(i,n) scanf("%d",&b[i]), b[i]--;cout<<inversion_number(inverse(permutation(b))*permutation(a))<<'\n';return 0;}