[题解] [HEOI2013] Segment

题面

题解

李超线段树

为了与机房大佬 HYJ 同步伐

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Code

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
const int N = 100005;
const int mod = 39989;
#define val(id, x) (k[id] * x + b[id])
using namespace std;

int Q, cnt, ans; 
struct node
{
	int id;
	double k, b; 
} t[N << 2];
double k[N], b[N]; 

template < typename T >
inline T read()
{
	T x = 0, w = 1; char c = getchar();
	while(c < '0' || c > '9') { if(c == '-') w = -1; c = getchar(); }
	while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
	return x * w; 
}

void pushtag(int p, int l, int r, int id)
{
	if(!t[p].id) { t[p] = (node) { id, k[id], b[id] }; return; }
	int now = t[p].id; 
	double l1 = val(now, l), r1 = val(now, r), l2 = val(id, l), r2 = val(id, r);
	if(l2 <= l1 && r2 <= r1) return;
	if(l1 < l2 && r1 < r2) { t[p] = (node) { id, k[id], b[id] }; return; }
	int mid = (l + r) >> 1; double x = (b[id] - b[now]) / (k[now] - k[id]);
	if(x <= mid)
	{
		if(l1 <= l2) pushtag(p << 1, l, mid, id);
		else pushtag(p << 1, l, mid, now), t[p] = (node) { id, k[id], b[id] }; 
	}
	else
	{
		if(l1 <= l2) pushtag(p << 1 | 1, mid + 1, r, now), t[p] = (node) { id, k[id], b[id] };
		else pushtag(p << 1 | 1, mid + 1, r, id); 
	}
}

void modify(int p, int l, int r, int ql, int qr, int id)
{
	if(ql <= l && r <= qr) { pushtag(p, l, r, id); return; }
	int mid = (l + r) >> 1;
	if(ql <= mid) modify(p << 1, l, mid, ql, qr, id);
	if(mid < qr) modify(p << 1 | 1, mid + 1, r, ql, qr, id); 
}

void check(int &a, int c, int x)
{
	double y0 = val(a, x), y1 = val(c, x);
	if(y1 > y0 || (fabs(y1 - y0) < 1e-7 && a > c)) a = c; 
}

int query(int p, int l, int r, int x)
{
	if(l == r) return t[p].id;
	int mid = (l + r) >> 1, res = t[p].id; 
	if(x <= mid) check(res, query(p << 1, l, mid, x), x);
	else check(res, query(p << 1 | 1, mid + 1, r, x), x);
	return res; 
}

int main()
{
/*	freopen("cpp.in", "r", stdin); 
	freopen("cpp.out", "w", stdout); 
*/	Q = read <int> ();
	int opt, x0, x1, y0, y1; 
	while(Q--)
	{
		opt = read <int> ();
		if(!opt)
		{
//			printf("%d
", x0); 
			x0 = read <int> (), x0 = ((x0 + ans - 1) % mod + 1); 
			printf("%d
", ans = query(1, 1, mod, x0)); 
		}
		else
		{
			x0 = read <int> (), y0 = read <int> (), x1 = read <int> (), y1 = read <int> ();
			x0 = ((x0 + ans - 1) % mod + 1), y0 = ((y0 + ans - 1) % 1000000000 + 1);
			x1 = ((x1 + ans - 1) % mod + 1), y1 = ((y1 + ans - 1) % 1000000000 + 1);
			if(x0 > x1) swap(x0, x1), swap(y0, y1);
//			printf("%d %d
", x0, x1); 
			k[++cnt] = 1.0 * (y1 - y0) / (x1 - x0), b[cnt] = 1.0 * y0 - k[cnt] * x0;
			modify(1, 1, mod, x0, x1, cnt); 
		}
	}
	return 0; 
}
/*
  3
  1 3 5 7 7
  1 3 9 7 3
  0 5
 */