Submission #399049

#	Time	Username	Problem	Language	Result	Execution time	Memory
399049		mshandilya	Arranging Shoes (IOI19_shoes)	C++14	0 / 100	1 ms	332 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"

using namespace std;

long long count_swaps(std::vector<int> s) {
	long long N = s.size(), left_pair = 0, right_pair = 0, sort_inversions = 0, total_inversions = 0;
    std::vector<int> position(N);
    std::vector<queue<int>> compensated_inversions(N+1);
    for(int i = 2*N-1; i>=0; i--) {
        if(s[i]<0) {
            compensated_inversions[abs(s[i])].push(left_pair);
            left_pair++;
            position[s[i]] = N-left_pair;
        }
        else if(!compensated_inversions[s[i]].empty()) {
            total_inversions += left_pair - compensated_inversions[s[i]].front();
            compensated_inversions[s[i]].pop();
        }
    }
    for(int i = 0; i<2*N-1; i++) {
        if(s[i]>0) {
            int cpos = position[s[i]];
            for(int j = i+1; j<2*N-1; j++)
                if(s[j]>0 && position[s[j]]<cpos)
                    sort_inversions++;
        }
    }
	return (total_inversions+sort_inversions);
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:7:41: warning: unused variable 'right_pair' [-Wunused-variable]
    7 |  long long N = s.size(), left_pair = 0, right_pair = 0, sort_inversions = 0, total_inversions = 0;
      |                                         ^~~~~~~~~~

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