你天天就看题解看题解，我真服了

理解可以，希望别直接抄
#include <bits/stdc++.h>

int N;
int ft[200005];

void update(int i, int v) {
for (; i <= N * 2; i += (i & -i)) {
ft[i] += v;
}
}

int query(int i) {
int ac = 0;
for (; i > 0; i -= (i & -i)) {
ac += ft[i];
}
return ac;
}

int uf[100005];

int find(int a) { return (a == uf[a]) ? a : (uf[a] = find(uf[a])); }

void merge(int a, int b) { uf[find(a)] = find(b); }

int st_lazy[800005];

int st_cnt[800005];

int who[200005];

void apply(int w, int v) {
if (!st_cnt[w]) return;
if (st_lazy[w]) {
merge(v, st_lazy[w]);
} else {
st_lazy[w] = v;
}
}

void push(int w, int L, int R) {
if (st_lazy[w]) {
if (R - L > 1) {
apply(w * 2 + 1, st_lazy[w]);
apply(w * 2 + 2, st_lazy[w]);
} else {
merge(st_lazy[w], who[R]);
}
st_lazy[w] = 0;
}
}

void pull(int w, int L, int R) {
assert(R - L > 1);
st_cnt[w] = st_cnt[w * 2 + 1] + st_cnt[w * 2 + 2];
}

void update_range_merge(int w, int L, int R, int a, int b, int v) {
push(w, L, R);
if (a >= R || b <= L) return;
if (a <= L && b >= R) {
apply(w, v);
push(w, L, R);
} else {
int M = (L + R) / 2;
update_range_merge(w * 2 + 1, L, M, a, b, v);
update_range_merge(w * 2 + 2, M, R, a, b, v);
pull(w, L, R);
}
}

void update_inc(int w, int L, int R, int i, int v) {
push(w, L, R);
if (i <= L || i > R) return;
if (R - L == 1) {
st_cnt[w] += v;
} else {
int M = (L + R) / 2;
update_inc(w * 2 + 1, L, M, i, v);
update_inc(w * 2 + 2, M, R, i, v);
pull(w, L, R);
}
}

void force_lazy(int w, int L, int R) {
push(w, L, R);
if (R - L > 1) {
int M = (L + R) / 2;
force_lazy(w * 2 + 1, L, M);
force_lazy(w * 2 + 2, M, R);
}
}

struct Event {
int l, r;
bool start;
int id;
} events[200005];

int exterior[100005];

bool vis[100005];

int main() {
int T;
scanf("%d %d", &N, &T);
for (int i = 1; i <= N; i++) {
int X1, Y1, X2, Y2;
scanf("%d %d %d %d", &X1, &Y1, &X2, &Y2);
events[X1] = Event{Y1, Y2, true, i};
events[X2] = Event{Y1, Y2, false, i};
who[Y1] = i;
who[Y2] = i;
}
for (int i = 1; i <= N; i++) {
uf[i] = i;
}
int corners[2] = {0, 0};
long long intersections = 0;
std::map<int, int> active;
for (int x = 1; x <= N * 2; x++) {
int l = events[x].l, r = events[x].r, id = events[x].id;
if (events[x].start) {
exterior[id] = query(l) % 2;
corners[query(l) % 2];
corners[query(r) % 2];
intersections += query(r) - query(l);
update_range_merge(0, 0, N * 2, l, r, id);
update(l, 1);
update(r, 1);
update_inc(0, 0, N * 2, l, 1);
update_inc(0, 0, N * 2, r, 1);
} else {
update(l, -1);
update(r, -1);
update_inc(0, 0, N * 2, l, -1);
update_inc(0, 0, N * 2, r, -1);
intersections += query(r) - query(l);
update_range_merge(0, 0, N * 2, l, r, id);
corners[query(l) % 2];
corners[query(r) % 2];
}
}
force_lazy(0, 0, N * 2);
int black_immersed = 0, white_immersed = 0; // cc surrounded by black/white
for (int x = 1; x <= N * 2; x++) {
int id = events[x].id;
if (events[x].start) {
if (!vis[find(id)]) {
if (exterior[id]) {
black_immersed++;
} else {
white_immersed++;
}
vis[find(id)] = true;
}
}
}
long long black_corners = corners[0] - corners[1] + intersections * 2;
long long white_corners = corners[1] - corners[0] + intersections * 2;
assert(black_corners % 4 == 0);
assert(white_corners % 4 == 0);
long long black_regions = black_corners / 4 + black_immersed;
long long white_regions = white_corners / 4 + white_immersed + 1;
if (T == 1) {
printf("%lld\n", white_regions + black_regions);
} else {
printf("%lld %lld\n", white_regions, black_regions);
}
}