Submission #73027

#	Time	Username	Problem	Language	Result	Execution time	Memory
73027		Benq	Ranklist Sorting (BOI07_sorting)	C++14	30 / 100	1070 ms	648 KiB

sorting

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;

int n;
vi s;

void compress() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> n; s.resize(n);
    map<int,int> m;
    F0R(i,n) {
        cin >> s[i];
        m[s[i]] = 0;
    }
    int co = 0;
    for (auto& a: m) a.s = co++;
    for (int& i: s) i = n-1-m[i];
}

pair<int,vpi> test(int z) {
    vpi S; F0R(i,sz(s)) S.pb({s[i],1});
    int lst = -1;
    F0R(i,n) {
        if (z&(1<<i)) S[i].s = 0;
        else {
            if (S[i].f < lst) return {MOD,{}};
            lst = S[i].f;
        }
    }
    vpi v;
    int cur = 0;
    F0Rd(i,n) {
        int ind = 0; while (S[ind].f != i) ind ++;
        if (S[ind].s) continue;
        cur += ind+1; S.erase(S.begin()+ind);
        int lst = 0;
        F0R(j,n-1) if (S[j].s && S[j].f < i) lst = j+1;
        cur += lst+1; S.insert(S.begin()+lst,{i,1});
        v.pb({ind+1,lst+1});
    }
    /*for (auto a: S) cout << a.f << " " << a.s << " | ";
    cout << "\n";*/
    return {cur,v};
}

int main() {
    compress();
    pair<int,vpi> ans = {MOD,{}};
    F0R(i,1<<n) ans = min(ans,test(i));
    cout << sz(ans.s) << "\n";
    for (auto a: ans.s) cout << a.f << " " << a.s << "\n";
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
* if you have no idea just guess the appropriate well-known algo instead of doing nothing :/
*/

• Subtask 1: 30 / 100