func_code_string: #include <bits/stdc++.h>   using namespace std;   const double eps = 1e-8;   const int mod = 1e9 + 7;   const int N = 4e5 + 10;   const int inf = 1e9;   int n, k, m;   map<pair<int, int>, int> vis;   int mx[N << 2], tag[N << 2];   int a[N];   void pd(int p, int k) {     mx[p << 1] += k;     tag[p << 1] += k;     mx[p << 1 | 1] += k;     tag[p << 1 | 1] += k;     tag[p] = 0;   }   void up(int dl, int dr, int l, int r, int p, int k) {     if (l == dl && r == dr) {       mx[p] += k;       tag[p] += k;       return;     }     int mid = l + r >> 1;     pd(p, tag[p]);     if (dr <= mid)       up(dl, dr, l, mid, p << 1, k);     else if (dl > mid)       up(dl, dr, mid + 1, r, p << 1 | 1, k);     else       up(dl, mid, l, mid, p << 1, k), up(mid + 1, dr, mid + 1, r, p << 1 | 1, k);     mx[p] = max(mx[p << 1], mx[p << 1 | 1]);   }   int main() {     ios::sync_with_stdio(false);     cin >> n >> k >> m;     for (int i = 1; i <= m; i++) {       int x, y;       cin >> x >> y;       int p = abs(x - k) + y;       if (vis[make_pair(x, y)]) {         up(1, p, 1, 2 * n, 1, -1);         a[p]--;         if (a[p] == 0) up(p, p, 1, 2 * n, 1, -p + 1);         vis[make_pair(x, y)] = 0;       } else {         up(1, p, 1, 2 * n, 1, 1);         if (a[p] == 0) up(p, p, 1, 2 * n, 1, p - 1);         ++a[p];         vis[make_pair(x, y)] = 1;       }       cout << max(0, mx[1] - n) <<   n ;     }     return 0;   }   