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OI-codes/S2OJ/1256/1256.cpp

141 lines
2.9 KiB
C++

#pragma GCC optimize("Ofast")
#include <cstdio>
#include <algorithm>
#include <cctype>
#include <cmath>
#include <vector>
const int N = 2e5 + 5;
int n;
long long ans;
std::vector<int> ys;
template <typename T>
void read(T& x) {
int f = 1;
char ch = getchar();
x = 0;
while (!isdigit(ch)) {
if (ch == '-') f = -1;
ch = getchar();
}
while (isdigit(ch)) {
x = x * 10 + ch - '0';
ch = getchar();
}
x *= f;
}
struct segment {
int x, y1, y2, k;
segment()
: x(0),
y1(0),
y2(0),
k(0) {}
segment(int _x, int _y1, int _y2, int _k)
: x(_x),
y1(_y1),
y2(_y2),
k(_k) {}
bool operator<(const segment& b) const {
return x == b.x ? k > b.k : x < b.x;
}
} seg[N << 1];
struct rectangle {
int x1, y1, x2, y2;
} q[N];
struct node {
int l, r;
long long cnt, len;
node()
: l(0),
r(0),
cnt(0),
len(0) {}
node(int _l, int _r)
: l(_l),
r(_r),
cnt(0),
len(0) {}
} tr[N << 3];
inline int find(int y) {
return std::lower_bound(ys.begin(), ys.end(), y) - ys.begin();
}
inline void pushup(int u) {
if (tr[u].cnt) {
tr[u].len = ys[tr[u].r + 1] - ys[tr[u].l];
} else if (tr[u].l != tr[u].r) {
tr[u].len = tr[u << 1].len + tr[u << 1 | 1].len;
} else {
tr[u].len = 0;
}
}
void build(int u, int l, int r) {
tr[u] = node(l, r);
if (l == r) return;
int mid = l + r >> 1;
build(u << 1, l, mid);
build(u << 1 | 1, mid + 1, r);
}
void modify(int u, int l, int r, int x) {
if (l <= tr[u].l && tr[u].r <= r) {
tr[u].cnt += x;
} else {
int mid = tr[u].l + tr[u].r >> 1;
if (l <= mid) modify(u << 1, l, r, x);
if (r > mid) modify(u << 1 | 1, l, r, x);
}
pushup(u);
}
void solve() {
std::sort(ys.begin(), ys.end());
std::sort(seg, seg + n * 2);
ys.erase(std::unique(ys.begin(), ys.end()), ys.end());
build(1, 0, ys.size() - 2);
for (int i = 0; i < n * 2; i++) {
int last = tr[1].len;
if (seg[i].y1 == seg[i].y2) continue;
modify(1, find(seg[i].y1), find(seg[i].y2) - 1, seg[i].k);
ans += abs(tr[1].len - last);
}
ys.clear();
}
int main() {
read(n);
for (int i = 0; i < n; i++) {
read(q[i].x1), read(q[i].y1), read(q[i].x2), read(q[i].y2);
}
for (int i = 0, j = 0; i < n; i++) {
seg[j++] = segment(q[i].x1, q[i].y1, q[i].y2, 1);
seg[j++] = segment(q[i].x2, q[i].y1, q[i].y2, -1);
ys.push_back(q[i].y1);
ys.push_back(q[i].y2);
}
solve();
for (int i = 0, j = 0; i < n; i++) {
seg[j++] = segment(q[i].y1, q[i].x1, q[i].x2, 1);
seg[j++] = segment(q[i].y2, q[i].x1, q[i].x2, -1);
ys.push_back(q[i].x1);
ys.push_back(q[i].x2);
}
solve();
printf("%lld\n", ans);
return 0;
}