Submission #761163

#	Time	Username	Problem	Language	Result	Execution time	Memory
761163		LucaLucaM	XORanges (eJOI19_xoranges)	C++17	100 / 100	76 ms	7924 KiB

xoranges

#include <bits/stdc++.h>

using namespace std;

const int NMAX = 2e5;

int a[NMAX + 5];

struct FenwickTree
{
    int n;
    vector<int>aib;
    void build (int _n)
    {
        n = _n + 1;
        aib.resize(n, 0);
    }
    void update (int pos, int val)
    {
        for (; pos < n; pos += pos & -pos)
            aib[pos] ^= val;
    }
    int query (int pos)
    {
        int ret = 0;
        for (; pos > 0; pos -= pos & -pos)
            ret ^= aib[pos];
        return ret;
    }
};

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, q;
    cin >> n >> q;
    FenwickTree aib[2];
    aib[0].build(n / 2 + 1);
    aib[1].build(n / 2 + 1);
    for (int i=2; i<=n+1; i++)
    {
        cin >> a[i];
        aib[i & 1].update(i / 2, a[i]);
    }
    while (q--)
    {
        int op, x, y;
        cin >> op >> x >> y;
        x++;
        if (op == 1)
        {
            int v = (a[x] ^ y);
            aib[x & 1].update(x / 2, v);
            a[x] = y;
        }
        else
        {
            y++;
            int ans = 0;
            if (x % 2 != y % 2)
            {
                cout << "0\n";
                continue;
            }
            if (x % 2 == 0)
            {
                x /= 2, y /= 2;
                cout << (aib[0].query(y) ^ aib[0].query(x - 1)) << '\n';
            }
            else
            {
                x /= 2, y /= 2;
                cout << (aib[1].query(y) ^ aib[1].query(x - 1)) << '\n';
            }
        }
    }
    return 0;
}

Compilation message (stderr)

xoranges.cpp: In function 'int main()':
xoranges.cpp:61:17: warning: unused variable 'ans' [-Wunused-variable]
   61 |             int ans = 0;
      |                 ^~~

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 25 / 25
• Subtask 4: 20 / 20
• Subtask 5: 25 / 25