软件包管理器

题目描述

思路

使用两个标记sum, flag(fg), sum表示安装软件的子节点有多少个；flag表示对这个区间的软件进行操作，1 全部安装，-1全部卸载，0不进行操作

代码

#include <cstdio>
#include <cstring>
#define lc k<<1
#define rc k<<1|1

const int MAX = 1e5 + 5;
int n, m, oa[100], ot, ans;
int head[MAX], ver[MAX << 1], nt[MAX << 1], ht;
int fa[MAX], size[MAX], son[MAX], dep[MAX];
int top[MAX], dfn[MAX], tr[MAX], dt;
int fg[MAX << 2], sum[MAX << 2];
char str[100], showStr[100];
inline int read() {
	int s = 0, f = 1;
	char ch = getchar();
	while (ch < '0' || ch > '9') {
		if (ch == '-') f = -1;
		ch = getchar();
	}
	while (ch >= '0' && ch <= '9') s = s * 10 + ch - '0', ch = getchar();
	return s * f;
}
void write(int x) {
	ot = 0;
	if (x == 0) { putchar('0'); return; }
	if (x < 0) putchar('-'), x = -x;
	while (x) oa[++ot] = x % 10 + '0', x /= 10;
	while (ot) putchar(oa[ot--]);
}
void add(int x, int y) {
	nt[++ht] = head[x], head[x] = ht, ver[ht] = y;
}
void dfs1(int x, int u) {
	fa[x] = u;
	dep[x] = dep[u] + 1;
	size[x] = 1;
	for (int i = head[x], j; i; i = nt[i]) {
		j = ver[i];
		dfs1(j, x);
		size[x] += size[j];
		if (size[j] > size[son[x]]) son[x] = j;
	}
}
void dfs2(int x, int u) {
	dfn[x] = ++dt;
	tr[dt] = x;
	top[x] = u;
	if (son[x]) dfs2(son[x], u);
	for (int i = head[x], j; i; i = nt[i]) {
		j = ver[i];
		if (!dfn[j]) dfs2(j, j);
	}
}


void pushdown(int k, int l, int r, int mid) {
	if (!fg[k]) return;
	fg[lc] = fg[rc] = fg[k];
	if (fg[k] == 1) sum[lc] = mid - l + 1, sum[rc] = r - mid;
	if (fg[k] == -1) sum[lc] = 0, sum[rc] = 0;
	fg[k] = 0;
}
void query(int k, int l, int r, int x, int y, int z) {
	if (x <= l && r <= y) {
		fg[k] = z;
		if (z == 1) {
			ans += r - l + 1 - sum[k];
			sum[k] = r - l + 1;
		} else {
			ans += sum[k];
			sum[k] = 0;
		}
		return;
	}
	int mid = l + r >> 1;
	pushdown(k, l, r, mid);
	if (x <= mid) query(lc, l, mid, x, y, z);
	if (y > mid) query(rc, mid + 1, r, x, y, z);
	sum[k] = sum[lc] + sum[rc];
}

void swap(int &x, int &y) {
	int t = x;
	x = y, y = t;
}

void ask(int x, int y) {
	int fx = top[x], fy = top[y];
	while (fx != fy) {
		if (dep[fx] < dep[fy]) swap(x, y), swap(fx, fy);
		query(1, 1, n, dfn[fx], dfn[x], 1);
		x = fa[fx], fx = top[x];
	}
	if (dep[x] > dep[y]) swap(x, y);
	query(1, 1, n, dfn[x], dfn[y], 1);
}
void showArr(int * arr) {
	printf("%s:", showStr);
	for (int i = 1; i <= n; ++i) printf("%2d ", arr[i]);
	puts("");
}
void show() {
	printf("n:%d m:%d
", n, m);
	for (int i = 1; i <= n; ++i) {
		printf("%d:", i);
		for (int j = head[i]; j; j = nt[j]) {
			printf("%d ", ver[j]);
		}
		puts("");
	}
	strcpy(showStr, "fa  :"), showArr(fa);
	strcpy(showStr, "size:"), showArr(size);
	strcpy(showStr, "son :"), showArr(son);
	strcpy(showStr, "dep :"), showArr(dep);
	strcpy(showStr, "top :"), showArr(top);
	strcpy(showStr, "dfn :"), showArr(dfn);
	strcpy(showStr, "tr  :"), showArr(tr);
	
}
int main() {
	n = read();
	for (int i = 2, j; i <= n; ++i) {
		j = read() + 1;
		add(j, i);
	}
	// show();
	dfs1(1, 0);
	dfs2(1, 1);
	m = read();
	// show();
	for (int i = 1, j; i <= m; ++i) {
		scanf("%s", str);
		j = read() + 1;
		ans = 0;
		if (strcmp("install", str) == 0) {
			ask(j, 1);
			write(ans), puts("");
		} else {
			query(1, 1, n, dfn[j], dfn[j] + size[j] - 1, -1);
			write(ans), puts("");
		}
	}
	return 0;
}