Submission #1034207

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034207		nickolasarapidis	Arranging Shoes (IOI19_shoes)	C++17	0 / 100	1 ms	432 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;

#define ll long long

ll count_swaps(vector<int> S){
	int N = S.size();

	deque<int> A(N);

	for(int i = 0; i < N; i++){
		A[i] = S[i];
	}

	ll ans = 0;

	while(N > 0){
		int a = A.front();

		if(a < 0 and A[1] == a + 2*a){
			A.pop_front();
			A.pop_front();
			N -= 2;
			continue;
		}

		if(a < 0){
			for(int i = 0; i < N; i++){
				if(A[i] == a + 2*a){
					int b = i;
					while(b != 1){
						swap(A[b], A[b - 1]);
						b--;
						ans++;
					}
				}
				break;
			}
			A.pop_front();
			A.pop_front();
			N -= 2;
		}
		else{
			for(int i = 0; i < N; i++){
				if(A[i] == a - 2*a){
					int b = i;
					while(b != 0){
						swap(A[b], A[b - 1]);
						b--;
						ans++;
					}
				}
				break;
			}
			A.pop_front();
			A.pop_front();
			N -= 2;
		}
	}

	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:33:22: warning: iteration 2147483648 invokes undefined behavior [-Waggressive-loop-optimizations]
   33 |       swap(A[b], A[b - 1]);
      |                    ~~^~~
shoes.cpp:32:14: note: within this loop
   32 |      while(b != 1){
      |            ~~^~~~

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