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