Submission #390632

#	Time	Username	Problem	Language	Result	Execution time	Memory
390632		mehrdad_sohrabi	Ancient Books (IOI17_books)	C++14	100 / 100	1006 ms	86924 KiB

books

#include <bits/stdc++.h>
#include "books.h"
using namespace std;
typedef long long int ll;
typedef complex<double> point;
typedef long double ld;
#define pb push_back
#define pii pair < ll , ll >
#define F first
#define S second
//#define endl '\n'
#define int long long
#define sync ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
#define kill(x) return cout<<x<<'\n', 0;
const int N=1e6+10,inf=(ll)1e9;

ll vis[N];
pii seg[N*4];
pii ba[N];
ll E[N];
void upd(ll nod,ll l,ll r,ll id,pii val){
    ba[id]=val;
    if (r-l==1){
        seg[nod]=val;
        return ;
    }
    ll mid=(r+l)/2;
    if (mid>id) upd(nod*2,l,mid,id,val);
    else upd(nod*2+1,mid,r,id,val);
    seg[nod].F=min(seg[nod*2].F,seg[nod*2+1].F);
    seg[nod].S=max(seg[nod*2].S,seg[nod*2+1].S);
}
pii get(ll nod,ll l,ll r,ll L,ll R){
    if (l>=R || L>=r) return {inf,0};
    if (l>=L && r<=R) return seg[nod];
    ll mid=(r+l)/2;
    pii a=get(nod*2,l,mid,L,R);
    pii b=get(nod*2+1,mid,r,L,R);
    return {min(a.F,b.F),max(a.S,b.S)};
}
long long minimum_walk(std::vector<int32_t> p, int32_t s) {
    memset(vis,0,sizeof vis);
    vector <pii> baz;
    ll n=p.size();
    ll ans=0;
    for (int i=0;i<n;i++){
       // cout << i << " rf" << endl;
       if (vis[i]) continue;
        if (p[i]==i){
            upd(1,0,n,i,{i,i});
            continue;
        }
        ll mn=i,mx=i;
        ll j=p[i];
        ans+=abs(p[i]-i);
        while(j!=i){
            ans+=abs(p[j]-j);
         //   cout << j << " " << p[j] << endl;
            mn=min(mn,j);
            mx=max(mx,j);
            vis[j]=1;
            j=p[j];
        }
         j=p[i];
        while(j!=i){
            upd(1,0,n,j,{mn,mx});
            j=p[j];
        }
        upd(1,0,n,i,{mn,mx});
        vis[i]=1;
        baz.pb({mn,-mx});
    }
 //   cout << ans << endl;
    sort(baz.begin(),baz.end());
    vector <pii> a;
    if (baz.size()){
    a.pb(baz[0]);
    for (int i=1;i<baz.size();i++){
        pii p=baz[i],q=a.back();
        if (-p.S<=-q.S) continue;
        if (p.F<=-q.S){
            a.pop_back();
            q.S=p.S;
            a.pb(q);
        }
        else
            a.pb(baz[i]);
    }
    for (auto u : a){
        for (int i=u.F;i<=-u.S;i++){
            E[i]++;
        }
    }
        ll p1=0;
        if (a[0].F>s){
            ans+=(a[0].F-s)*2;
            p1=1;
        }
        if (-a.back().S<s){
            ans+=(s+a.back().S)*2;
            p1=1;
        }
        if (p1==0 && E[s]!=0){
            pii b={s,s};
            while(true){

                while(true){
                    pii z=get(1,0,n,b.F,b.S+1);
                    if (z!=b) b=z;
                    else break;
                }
                ll z=lower_bound(a.begin(),a.end(),pii({b.F,-inf}))-a.begin();
              //  cout << b.F << "  dc " << b.S << endl;
                if (z==a.size() || a[z].F!=b.F){
                    b.F--;
                    b.S++;
                    ans+=2;
                }
                else break;
            }
        }
        for (int i=1;i<a.size();i++){
            ans+=(a[i].F+a[i-1].S)*2;
        }
    }
    return ans;
}
/*
int32_t main() {
	int32_t n, s;
	assert(2 == scanf("%d %d", &n, &s));

	vector<int32_t> p((unsigned) n);
	for(int i = 0; i < n; i++)
		assert(1 == scanf("%d", &p[(unsigned) i]));

	long long res = minimum_walk(p, s);
	printf("%lld\n", res);

	return 0;
}
*/
/*
4 0
0 2 3 1
4 2
1 3 2 0
*/

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int32_t)':
books.cpp:79:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |     for (int i=1;i<baz.size();i++){
      |                  ~^~~~~~~~~~~
books.cpp:115:22: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  115 |                 if (z==a.size() || a[z].F!=b.F){
      |                     ~^~~~~~~~~~
books.cpp:123:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  123 |         for (int i=1;i<a.size();i++){
      |                      ~^~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 20 / 20
• Subtask 5: 30 / 30