bzoj1858

线段树模板题

#include <cstdio>
#include <iostream>
using namespace std;
int n,m,f,u,v;

int l0[400010],r0[400010],m0[400010],l1[400010],r1[400010],m1[400010];
int l[400010],r[400010],lz[400010],sum[400010];

int read_int () {
	char c = getchar();
	int re = 0;
	for(;c > '9' || c < '0'; c = getchar());
	for(;c >= '0' && c <= '9';c = getchar())
		re = re * 10 + c - '0';
	return re;
}

void push_up (int M) {
	int ls = M << 1;
	int rs = ls | 1;
	sum[M] = sum[ls] + sum[rs];
	
	l0[M] = l0[ls];
	if(l0[M] == r[ls] - l[ls] + 1)
		l0[M] += l0[rs];
	r0[M] = r0[rs];
	if(r0[M] == r[rs] - l[rs] + 1)
		r0[M] += r0[ls];
	m0[M] = max(m0[ls],m0[rs]);
	m0[M] = max(m0[M],l0[rs] + r0[ls]);
	
	l1[M] = l1[ls];
	if(l1[M] == r[ls] - l[ls] + 1)
		l1[M] += l1[rs];
	r1[M] = r1[rs];
	if(r1[M] == r[rs] - l[rs] + 1)
		r1[M] += r1[ls];
	m1[M] = max(m1[ls],m1[rs]);
	m1[M] = max(m1[M],l1[rs] + r1[ls]);
}

void build (int L,int R,int M) {
	l[M] = L;
	r[M] = R;
	if(L == R) {
		sum[M] = read_int();
		if(sum[M])
			l1[M] = r1[M] = m1[M] = 1;
		else l0[M] = r0[M] = m0[M] = 1;
		return;
	}
	int mid = (L + R) / 2;
	build(L,mid,M << 1);
	build(mid + 1,R,M << 1 | 1);
	push_up(M);
}

void modi_0 (int M) {
	l0[M] = r0[M] = m0[M] = r[M] - l[M] + 1;
	sum[M] = l1[M] = r1[M] = m1[M] = 0;
	lz[M] = 1;	
}

void modi_1 (int M) {
	l0[M] = r0[M] = m0[M] = 0;
	sum[M] = l1[M] = r1[M] = m1[M] = r[M] - l[M] + 1;
	lz[M] = 2;	
}

void swp (int &a,int &b) {
	int t = a;
	a = b;
	b = t;
}

void modi_2 (int M) {
	swp(l0[M],l1[M]);
	swp(r0[M],r1[M]);
	swp(m0[M],m1[M]);
	sum[M] = r[M] - l[M] + 1 - sum[M];
	if(lz[M] == 1)
		lz[M] = 2;
	else {
		if(lz[M] == 2)
			lz[M] = 1;
		else {
			if(lz[M] == 3)
				lz[M] = 0;
			else lz[M] = 3;
		}
	}
}

void push_down (int M) {
	if(!lz[M])
		return;
	if(lz[M] == 1) {
		modi_0(M << 1);
		modi_0(M << 1 | 1);
	}
	else {
		if(lz[M] == 2) {
			modi_1(M << 1);
			modi_1(M << 1 | 1);
		}
		else {
			modi_2(M << 1);
			modi_2(M << 1 | 1);
		}
	}
	lz[M] = 0;
}

void change (int f,int L,int R,int M) {
	if(l[M] == L && r[M] == R) {
		if(f == 0)
			modi_0(M);
		else 
			if(f == 1)
				modi_1(M);
			else modi_2(M);
		return;
	}
	push_down(M);
	int mid = (l[M] + r[M]) / 2;
	if(L > mid)
		change(f,L,R,M << 1 | 1);
	else 
		if(R <= mid)
			change(f,L,R,M << 1);
		else {
			change(f,L,mid,M << 1);
			change(f,mid + 1,R,M << 1 | 1);
		}
	push_up(M);
}

int find_sum (int L,int R,int M) {
	if(L == l[M] && R == r[M])
		return sum[M];
	
	push_down(M);
	int mid = (l[M] + r[M]) / 2;
	if(R <= mid)	
		return find_sum(L,R,M << 1);
	else 
		if(L > mid)
			return find_sum(L,R,M << 1 | 1);
		else return find_sum(L,mid,M << 1) + find_sum(mid + 1,R,M << 1 | 1);
}

int find_1 (int L,int R,int &ll1,int &rr1,int M) {
	if(L == l[M] && R == r[M]) {
		ll1 = l1[M];
		rr1 = r1[M];
		return m1[M];
	}
	push_down(M);
	int mid = (l[M] + r[M]) / 2;
	if(L > mid)
		return find_1(L,R,ll1,rr1,M << 1 | 1);
	else 
		if(R <= mid)
			return find_1(L,R,ll1,rr1,M << 1);
		else {
			int re,lll1,lrr1,rll1,rrr1,lm1,rm1;
			lm1 = find_1(L,mid,lll1,lrr1,M << 1);
			rm1 = find_1(mid + 1,R,rll1,rrr1,M << 1 | 1);


			ll1 = lll1;
			if(ll1 == mid - L + 1)
				ll1 += rll1;
			rr1 = rrr1;
			if(rr1 == R - mid)
				rr1 += lrr1;
			re = max(lm1,rm1);
			return re = max(re,lrr1 + rll1);
		}
}

int main () {
	n = read_int();
	m = read_int();
	
	build(1,n,1);
	
	int ll1,rr1;
	for(int i = 1;i <= m;++i) {
		f = read_int();
		u = read_int() + 1;
		v = read_int() + 1;
		if(f <= 2)
			change(f,u,v,1);
		else {
			if(f == 3)
				printf("%d\n",find_sum(u,v,1));
			else printf("%d\n",find_1(u,v,ll1,rr1,1));
		}
	}
}