Submission #618994

#	Time	Username	Problem	Language	Result	Execution time	Memory
618994		serize	Arranging Shoes (IOI19_shoes)	C++17	30 / 100	1092 ms	5252 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
#include <cstdio>
#include <cassert>
#define all(x) x.begin(),x.end()

using namespace std;

long long count_swaps(std::vector<int> s) {
	int n = (int)s.size();
    if(n <= 16){
        vector<int> neg;
        for(int i = 0; i < n; i++){
            if(s[i] < 0){
                neg.push_back(i);
            }
        }
        const int MAX = 16;
        bitset<MAX> mark;
        int ans = INT32_MAX;
        do{
            mark.reset();
            vector<int> ar(n);
            int aux = 0;
            for(int i = 0; i < n/2; i++){
                ar[aux] = neg[i];
                for(int j = 0; j < n; j++){
                    if(mark[j] == false and s[j] == -s[ar[aux]]){
                        ar[aux+1] = j;
                        mark[j] = true;
                        break;
                    }
                }
                aux += 2;
            }
            vector<int> pos(n), num(n);
            for(int i = 0; i < n; i++) pos[i] = num[i] = i;
            int swp = 0;
            for(int i = 0; i < n; i++){
                swp += abs(i-pos[ar[i]]);
                if(pos[ar[i]] < i){
                    for(int j = pos[ar[i]]+1; j <= i; j++){
                        pos[ num[j] ]--;
                    }
                    pos[ ar[i] ] = i;
                }
                if(i < pos[ar[i]]){
                    for(int j = pos[ar[i]]-1; j >= i; j--){
                        pos[num[j]]++;
                    }
                    pos[ ar[i] ] = i;
                }
                for(int i = 0; i < n; i++) num[pos[i]] = i;
            }
            ans = min(ans,swp);
            
        }while(next_permutation(all(neg)));
        return ans;
    }
    else{
        queue<int> neg, pos;
        for(int i = 0; i < n; i++){
            if(s[i] < 0) neg.push(i);
            else pos.push(i);
        }
        vector<int> ar(n);
        for(int i = 0; i < n-1; i+=2){
            ar[i] = neg.front(); neg.pop();
            ar[i+1] = pos.front(); pos.pop();
        }
        vector<int> position(n), num(n);
        for(int i = 0; i < n; i++) position[i] = num[i] = i;
        int swp = 0;
        for(int i = 0; i < n; i++){
            swp += abs(i-position[ar[i]]);
            if(position[ar[i]] < i){
                for(int j = position[ar[i]]+1; j <= i; j++){
                    position[ num[j] ]--;
                }
                position[ ar[i] ] = i;
            }
            if(i < position[ar[i]]){
                for(int j = position[ar[i]]-1; j >= i; j--){
                    position[num[j]]++;
                }
                position[ ar[i] ] = i;
            }
            for(int i = 0; i < n; i++) num[position[i]] = i;
        }
        return swp;
    }
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15