Submission #67979

#	Time	Username	Problem	Language	Result	Execution time	Memory
67979		cdemirer	XOR Sum (info1cup17_xorsum)	C++17	0 / 100	1674 ms	27976 KiB

xorsum

#include <bits/stdc++.h>
#include <limits>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ii> vii;
typedef vector<vii> vvii;
typedef pair<double, double> dodo;
typedef pair<ll, ll> llp;
#define mp(x, y) make_pair(x, y)
#define pb(x) push_back(x)


ll N;
vector<ll> A;
ll ans[31] = {0};

int main(int argc, char **argv) {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	cin >> N;
	A.resize(N);
	for (int i = 0; i < N; i++) cin >> A[i];
	
	for (ll k = 0; k < 31; k++) {
		vector<ll> B;
		for (int i = 0; i < A.size(); i++) if (!(A[i] & (1<<k))) B.pb(A[i]);
		for (int i = 0; i < A.size(); i++) if ((A[i] & (1<<k))) B.pb(A[i]);
		A = B;
		llp limits = mp(1<<k, 1<<(k+1));
		llp range = mp(N-1, N-1);
		ll cnt = 0;
		for (int i = 0; i < N; i++) {
			while (range.first >= 0 && A[range.first]%(1<<(k+1)) + A[i]%(1<<(k+1)) > limits.first) range.first--;
			while (range.second >= 0 && A[range.second]%(1<<(k+1)) + A[i]%(1<<(k+1)) > limits.second) range.second--;
			ans[k] += range.second - range.first;
			if (i > range.first && i <= range.second) cnt++;
		}
		ll limit = (1<<(k+1)) + (1<<k);
		range = mp(N-1, N-1);
		for (int i = 0; i < N; i++) {
			while (range.first >= 0 && A[range.first]%(1<<(k+1)) + A[i]%(1<<(k+1)) > limit) range.first--;
			ans[k] += range.second - range.first;
			if (i > range.first && i <= range.second) cnt++;
		}
		ans[k] = (ans[k]+cnt)/2;
	}
	ll out = 0;
	for (int k = 0; k < 31; k++) {
		out |= ((ans[k]%2)<<k);
	}
	cout << out-1 << endl;

	return 0;
}

Compilation message (stderr)

xorsum.cpp: In function 'int main(int, char**)':
xorsum.cpp:30:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < A.size(); i++) if (!(A[i] & (1<<k))) B.pb(A[i]);
                   ~~^~~~~~~~~~
xorsum.cpp:31:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < A.size(); i++) if ((A[i] & (1<<k))) B.pb(A[i]);
                   ~~^~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 38
• Subtask 5: 0 / 23