LITES (Segment Tree)

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

const int N = 1e5;

int n;
int st[4 * N], com[4 * N];

void update(int x, int y, int id, int l, int r)
{
    if (r <= l || r <= x || y <= l) return;

    if (x <= l && r <= y) {
        ++com[id];
        st[id] = r-l-st[id];
    }
    else {
        int mid = (l+r) / 2;
        update(x, y, 2*id+1, l, mid);
        update(x, y, 2*id+2, mid, r);

        st[id] = st[2*id+1] + st[2*id+2];

        if (com[id] % 2 == 1)
            st[id] = r-l-st[id];
    }
}

int get(int x, int y, int id, int l, int r)
{
    if(r <= l || r <= x || y <= l)
        return 0;
    if(x <= l && r <= y)
        return st[id];

    int mid = (l+r) / 2;
    int res = get(x, y, 2*id+1, l, mid) + get(x, y, 2*id+2, mid, r);

    return com[id] % 2 == 0 ? res : min(r, y) - max(l, x) - res;
}

int main()
{
    int q; cin >> n >> q;

    while (q-- > 0) {
        int t, x, y;
        cin >> t >> x >> y;

        if (t == 0)
            update(x-1, y, 0, 0, n);
        else {
            cout << get(x-1, y, 0, 0, n);
            cout << '\n';
        }
    }

    return 0;
}