Submission #369363

#	Time	Username	Problem	Language	Result	Execution time	Memory
369363		doowey	Cheerleaders (info1cup20_cheerleaders)	C++14	100 / 100	1854 ms	19068 KiB

cheerleaders

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

int main(){
    fastIO;
    int n;
    cin >> n;
    if(n == 0){
        cout << 0 << "\n";
        return 0;
    }
    int m = (1 << n);
    vector<int> H(m);
    for(int i = 0 ; i < m ; i ++ ){
        cin >> H[i];
    }
    ll best = (ll)1e18;
    vector<int> soln;
    ll cur;
    ll inv;
    ll w0, w1;
    int pp;
    int z;
    vector<int> cha;
    for(int shf = 0; shf < n; shf ++ ){
        vector<int> ord;
        vector<bool> swi(n);
        for(int j = shf; j < n - 1; j ++) {
            ord.push_back(j);
        }
        ord.push_back(n-1);
        for(int j = 0 ; j < shf; j ++ ){
            ord.push_back(j);
        }
        vector<vector<pii>> pv;
        vector<vector<pii>> nw;
        pv.push_back({});
        cur = 0;
        for(int i = 0 ;i < m ; i ++ ){
            pv.back().push_back(mp(H[i],i));
        }
        sort(pv.back().begin(), pv.back().end());
        cha.clear();
        for(int i = n - 1; i >= 0; i -- ){
            nw.clear();
            w0 = w1 = 0;
            for(auto x : pv){
                vector<pii> f[2];
                for(auto y : x){
                    if((y.se & (1 << ord[i]))){
                        f[1].push_back(y);
                    }
                    else{
                        f[0].push_back(y);
                    }
                }
                pp = 0;
                inv = 0;
                z = f[0].size();
                for(auto x : f[0]){
                    while(pp < f[1].size() && f[1][pp].fi < x.fi){
                        pp ++ ;
                    }
                    inv += pp;
                }
                w0 += inv;
                w1 += (z * 1ll * z) - inv;
                nw.push_back(f[0]);
                nw.push_back(f[1]);
            }
            pv = nw;
            if(w0 < w1){
                cur += w0;
            }
            else{
                cur += w1;
                swi[ord[i]]=true;
            }
        }
        if(cur < best){
            best = cur;
            soln.clear();
            for(int j = 0 ; j < n; j ++ ){
                if(swi[(j + n - 1) % n]) soln.push_back(1);
                soln.push_back(2);
            }
            for(int j = 0; j < shf; j ++ ){
                soln.push_back(2);
            }
        }
    }
    cout << best << "\n";
    for(auto x : soln) cout << x;
    return 0;
}

Compilation message (stderr)

cheerleaders.cpp: In function 'int main()':
cheerleaders.cpp:70:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |                     while(pp < f[1].size() && f[1][pp].fi < x.fi){
      |                           ~~~^~~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 21 / 21
• Subtask 5: 28 / 28