洛谷P4344 [SHOI2015]脑洞治疗仪(ODT)

题意

题目链接

Sol

ODT板子题。

操作1直接拆区间就行。

#include<bits/stdc++.h>
#define fi first
#define se second
const int MAXN = 2e5 + 10;
using namespace std;
inline int read() {
	char c = getchar(); int x = 0, f = 1;
	while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
	while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
	return x * f;
}
int N, M;
#define sit set<Node>::iterator
struct Node {
	int l, r;
	mutable int v;
	bool operator < (const Node &rhs) const {
		return l < rhs.l;
	}
};
set<Node> s;
sit split(int p) {
	sit pos = s.lower_bound({p, 0, 0});
	if(pos->l == p) return pos;
	pos--;
	int L = pos->l, R = pos->r, V = pos->v;
	s.erase(pos);
	s.insert({L, p - 1, V});
	return s.insert({p, R, V}).fi;
}
void Mem(int l, int r) {
	sit ed = split(r + 1), bg = split(l);
	s.erase(bg, ed);
	s.insert({l, r, 0});
}
void Fix(int l0, int r0, int l, int r) {
	int num = 0;
	sit ed = split(r + 1), bg = split(l);
	for(sit i = bg; i != ed; i++) if(i->v == 1) num += i->r - i->l + 1;
	s.erase(bg, ed);
	s.insert({l, r, 0});
	ed = split(r0 + 1), bg = split(l0);
	sit gg; int RR = -1;
	for(sit i = bg; i != ed; i++) {
		if(i -> v == 1) continue;
		if(num <= 0) return ;
		int len = i->r - i->l + 1;
		if(len <= num) {i -> v = 1, num -= len; gg = i; RR = i->r; continue;}
		int L = i->l, R = i->r;
		s.erase(i);
		s.insert({L, L + num - 1, 1});
		s.insert({L + num, R, 0});
		return ;
	}
	if(RR > l0) {//Ò»¸ö²¢Ã»ÓÐʲôÂÑÓõÄÓÅ»¯
		gg++;
		s.erase(bg, gg);
		s.insert({l0, RR, 1});
	}
}
int Query(int l, int r) {
	sit ed = split(r + 1), bg = split(l);
	int pre = 0, ans = 0;
	for(sit i = bg; i != ed; i++) {
		if(i->v == 0) ans = max(ans, i->r - i->l + 1 + pre), pre += i->r - i->l + 1;
		else pre = 0;
	}
	return ans;
}
int main() {
	//freopen("a.in", "r", stdin);
	N = read(); M = read();
	for(int i = 1; i <= N; i++) s.insert({i, i, 1});
	s.insert({N + 1, N + 1, 1});
	for(int i = 1; i <= M; i++) {
		int opt = read(), l = read(), r = read();
		if(opt == 0) Mem(l, r);
		else if(opt == 1) {
			int l1 = read(), r1 = read();
			Fix(l1, r1, l, r);
		} else printf("%d\n", Query(l, r));
	}
	return 0;
}