HDU 3397 Sequence operation 线段树

最新推荐文章于 2019-10-06 08:12:56 发布

转载最新推荐文章于 2019-10-06 08:12:56 发布 · 71 阅读

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原文链接：http://www.cnblogs.com/rolight/p/3915127.html

本文详细介绍了一种高效的数据结构——线段树，并通过具体实现展示了如何利用线段树进行区间更新与查询操作。适用于解决计算机科学中涉及区间操作的问题。

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线段树大杂烩~ 各种操作都有，细心点不难1A

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>

using namespace std;

#define lson rt<<1,l,mid
#define rson rt<<1|1,mid + 1,r
const int maxn = 1e5 + 10;
int lmax[maxn << 2][2], rmax[maxn << 2][2], mmax[maxn << 2][2];
int lazy_xor[maxn << 2], lazy_cover[maxn << 2], sum[maxn << 2];
int N, M, val[maxn];

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

void change_xor(int rt, int l, int r) {
	swap(lmax[rt][0], lmax[rt][1]);
	swap(rmax[rt][0], rmax[rt][1]);
	swap(mmax[rt][0], mmax[rt][1]);
	sum[rt] = r - l + 1 - sum[rt];
}

void change_cover(int rt, int l, int r, int Val) {
	for (int i = 0; i < 2; i++) 
		lmax[rt][i] = rmax[rt][i] = mmax[rt][i] =
			Val == i ? r - l + 1 : 0;
	sum[rt] = Val * (r - l + 1);
}

void pushup(int rt, int l, int r) {
	int lc = rt << 1, rc = rt << 1 | 1, mid = (l + r) >> 1;
	int Llen = mid - l + 1, Rlen = r - mid;
	for (int i = 0; i < 2; i++) {
		lmax[rt][i] = lmax[lc][i];
		rmax[rt][i] = rmax[rc][i];
		mmax[rt][i] = max(mmax[lc][i], mmax[rc][i]);
		if (lmax[rc][i] != 0 && rmax[lc][i] != 0) {
			if (lmax[lc][i] == Llen)
				lmax[rt][i] += lmax[rc][i];
			if (rmax[rc][i] == Rlen)
				rmax[rt][i] += rmax[lc][i];
			mmax[rt][i] = max(mmax[rt][i], rmax[lc][i] + lmax[rc][i]);
			mmax[rt][i] = max(mmax[rt][i], lmax[rt][i]);
			mmax[rt][i] = max(mmax[rt][i], rmax[rt][i]);
		}
	}
	sum[rt] = sum[lc] + sum[rc];
}

void pushdown_cover(int rt, int l, int r) {
	int lc = rt << 1, rc = rt << 1 | 1, mid = (l + r) >> 1;
	lazy_cover[lc] = lazy_cover[rc] = lazy_cover[rt];
	lazy_xor[lc] = lazy_xor[rc] = 0;
	change_cover(lson, lazy_cover[rt]);
	change_cover(rson, lazy_cover[rt]);
	lazy_cover[rt] = -1;
}

void pushdown_xor(int rt, int l, int r) {
	int lc = rt << 1, rc = rt << 1 | 1, mid = (l + r) >> 1;
	if (lazy_cover[lc] == -1) lazy_xor[lc] ^= 1, change_xor(lson);
	else lazy_cover[lc] ^= 1, change_cover(lson,lazy_cover[lc]);
	if (lazy_cover[rc] == -1) lazy_xor[rc] ^= 1, change_xor(rson);
	else lazy_cover[rc] ^= 1, change_cover(rson, lazy_cover[rc]);
	lazy_xor[rt] = 0;
}

void pushdown(int rt, int l, int r) {
	if (lazy_cover[rt] != -1) pushdown_cover(rt, l, r);
	if (lazy_xor[rt] != 0) pushdown_xor(rt, l, r);
}

void build(int rt, int l, int r) {
	int mid = (l + r) >> 1;
	if (l == r) {
		change_cover(rt, l, r, val[l]);
		lazy_cover[rt] = -1; lazy_xor[rt] = 0;
		sum[rt] = val[l];
	}
	else {
		lazy_cover[rt] = -1; lazy_xor[rt] = 0;
		build(lson); build(rson);
		pushup(rt, l, r);
	}
}

void update(int rt, int l, int r, int ql, int qr, int Val) {
	if (ql <= l && qr >= r) {
		if (Val == 2) {
			if (lazy_cover[rt] == -1) {
				change_xor(rt, l, r); lazy_xor[rt] ^= 1;
			}
			else {
				lazy_cover[rt] ^= 1;
				change_cover(rt,l,r,lazy_cover[rt]);
			}
		}
		else {
			lazy_cover[rt] = Val; lazy_xor[rt] = 0;
			change_cover(rt, l, r, lazy_cover[rt]);
		}
	}
	else {
		int mid = (l + r) >> 1;
		pushdown(rt, l, r);
		if (ql <= mid) update(lson, ql, qr, Val);
		if (qr > mid) update(rson, ql, qr, Val);
		pushup(rt, l, r);
	}
}

int query_sum(int rt, int l, int r, int ql, int qr) {
	if (ql <= l && qr >= r) return sum[rt];
	pushdown(rt, l, r);
	int mid = (l + r) >> 1, ret = 0;
	if (ql <= mid) ret += query_sum(lson, ql, qr);
	if (qr > mid) ret += query_sum(rson, ql, qr);
	return ret;
}

int query_len(int rt, int l, int r, int ql, int qr) {
	int mid = (l + r) >> 1, lc = rt << 1, rc = rt << 1 | 1;
	if (ql <= l && qr >= r) return mmax[rt][1];
	pushdown(rt, l, r);
	if (ql > mid) return query_len(rson, ql, qr);
	if (qr <= mid) return query_len(lson, ql, qr);
	//如果最长的连续出现在左边或者右边
	int Lmax = query_len(lson, ql, mid), Rmax = query_len(rson, mid + 1, qr);
	//或者是出现在中间
	int Lpos, Rpos, Mmax;
	Lpos = max(ql, mid - rmax[lc][1] + 1);
	Rpos = min(qr, mid + lmax[rc][1]);
	Mmax = Rpos - Lpos + 1;
	return max(Mmax, max(Lmax, Rmax));
}

void Handle(int cmd, int a, int b) {
	if (cmd == 0 || cmd == 1 || cmd == 2) update(1, 1, N, a, b, cmd);
	if (cmd == 3) printf("%d\n", query_sum(1, 1, N, a, b));
	if (cmd == 4) printf("%d\n", query_len(1, 1, N, a, b));
}

int main() {
	int T; scanf("%d", &T);
	for (int kase = 1; kase <= T; kase++) {
		scanf("%d%d", &N, &M);
		for (int i = 1; i <= N; i++) scanf("%d", &val[i]);
		build(1, 1, N);
		for (int i = 0; i < M; i++) {
			int cmd, a, b;
			scanf("%d%d%d", &cmd, &a, &b);
			Handle(cmd, a + 1, b + 1);
		}
	}
	return 0;
}

转载于:https://www.cnblogs.com/rolight/p/3915127.html