Submission #828641

#	Time	Username	Problem	Language	Result	Execution time	Memory
828641		rainboy	Arboras (RMI20_arboras)	C11	100 / 100	111 ms	21464 KiB

arboras

#include <stdio.h>
#include <stdlib.h>

#define N	100000
#define N_	(1 << 17)	/* N_ = pow2(ceil(log2(N + 1))) */
#define MD	1000000007

long long max(long long a, long long b) { return a > b ? a : b; }

int *ej[N], eo[N], n;

void append(int i, int j) {
	int o = eo[i]++;

	if (o >= 2 && (o & o - 1) == 0)
		ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
	ej[i][o] = j;
}

int dd[N], pp[N], qq[N], jj[N], jj1[N], jj2[N], ta[N], tb[N], qu[N], ww[N]; long long dp[N];

int dfs1(int p, int i, int d) {
	int o, s, k_, j_, j1, j2;

	dd[i] = d, pp[i] = p;
	s = 1, k_ = 0, j_ = -1, j1 = -1, j2 = -1;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			int k = dfs1(i, j, d + 1);

			s += k;
			if (k_ < k)
				k_ = k, j_ = j;
			dp[j] += ww[j];
			if (j1 == -1 || dp[j1] < dp[j])
				j2 = j1, j1 = j;
			else if (j2 == -1 || dp[j2] < dp[j])
				j2 = j;
		}
	}
	jj[i] = j_;
	dp[i] = j1 == -1 ? 0 : dp[j1], jj1[i] = j1, jj2[i] = j2;
	return s;
}

long long st[N_ * 2], lz[N_]; int h_, n_;

void put(int i, long long x) {
	st[i] += x;
	if (i < n_)
		lz[i] += x;
}

void pus(int i) {
	if (lz[i])
		put(i << 1 | 0, lz[i]), put(i << 1 | 1, lz[i]), lz[i] = 0;
}

void pul(int i) {
	if (!lz[i])
		st[i] = max(st[i << 1 | 0], st[i << 1 | 1]);
}

void push(int i) {
	int h;

	for (h = h_; h > 0; h--)
		pus(i >> h);
}

void pull(int i) {
	while (i > 1)
		pul(i >>= 1);
}

void build() {
	static long long dd[N + 1];
	int i;

	for (i = 1; i < n; i++)
		dd[ta[i]] += ww[i], dd[tb[i]] -= ww[i];
	for (i = 1; i < n; i++)
		dd[i] += dd[i - 1];
	for (i = 0; i < n_; i++)
		st[n_ + i] = i < n ? dd[i] : 0;
	for (i = n_ - 1; i > 0; i--)
		pul(i);
}

void update(int l, int r, int x) {
	int l_ = l += n_, r_ = r += n_;

	push(l_), push(r_);
	for ( ; l <= r; l >>= 1, r >>= 1) {
		if ((l & 1) == 1)
			put(l++, x);
		if ((r & 1) == 0)
			put(r--, x);
	}
	pull(l_), pull(r_);
}

long long query(int l, int r) {
	long long x;

	push(l += n_), push(r += n_);
	x = 0;
	for ( ; l <= r; l >>= 1, r >>= 1) {
		if ((l & 1) == 1)
			x = max(x, st[l++]);
		if ((r & 1) == 0)
			x = max(x, st[r--]);
	}
	return x;
}

int st_[N_ * 2];

void pul_(int i) {
	st_[i] = st_[i << 1 | 0] && st_[i << 1 | 1];
}

void update_(int i, int x) {
	st_[i += n_] = x;
	while (i > 1)
		pul_(i >>= 1);
}

int query_(int r) {
	int l = 0;

	for (l += n_, r += n_; l <= r; l >>= 1, r >>= 1)
		if ((r & 1) == 0) {
			if (!st_[r]) {
				while (r < n_)
					r = !st_[r << 1 | 1] ? r << 1 | 1 : r << 1 | 0;
				return r - n_;
			}
			r--;
		}
	return -1;
}

void dfs2(int p, int i, int q) {
	static int time;
	int o, j_;

	qu[ta[i] = time++] = i;
	qq[i] = q;
	j_ = jj[i];
	if (j_ != -1) {
		dfs2(i, j_, q);
		update_(ta[j_], j_ == jj1[i]);
	}
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p && j != j_)
			dfs2(i, j, j);
	}
	tb[i] = time;
}

int main() {
	int q, i, j, w, sum;

	scanf("%d", &n);
	for (i = 0; i < n; i++)
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
	for (j = 1; j < n; j++) {
		scanf("%d", &pp[j]);
		append(pp[j], j);
	}
	for (j = 1; j < n; j++)
		scanf("%d", &ww[j]);
	dfs1(-1, 0, 0);
	while (1 << h_ <= n)
		h_++;
	n_ = 1 << h_;
	dfs2(-1, 0, 0);
	build();
	sum = 0;
	for (i = 0; i < n; i++)
		sum = (sum + (jj1[i] == -1 ? 0 : dp[jj1[i]]) + (jj2[i] == -1 ? 0 : dp[jj2[i]])) % MD;
	scanf("%d", &q);
	printf("%d\n", sum);
	while (q--) {
		int x;
		long long d, d1, d2;

		scanf("%d%d", &j, &w);
		update(ta[j], tb[j] - 1, w);
		ww[j] += w, x = w;
		while (1) {
			i = qu[query_(ta[j])];
			sum = (sum + (long long) x * (dd[j] - dd[i])) % MD;
			j = i;
			if (j == 0)
				break;
			i = pp[j];
			if (jj1[i] == j)
				sum = (sum + x) % MD;
			else {
				d = query(ta[j], tb[j] - 1);
				d1 = query(ta[jj1[i]], tb[jj1[i]] - 1);
				d2 = query(ta[jj2[i]], tb[jj2[i]] - 1);
				if (d1 < d) {
					sum = (sum + (j == jj2[i] ? x : d - d2)) % MD;
					x = d - d1;
					jj2[i] = jj1[i], jj1[i] = j;
					update_(ta[jj[i]], jj[i] == j);
				} else {
					if (jj2[i] == j)
						sum = (sum + x) % MD;
					else if (d2 < d) {
						sum = (sum + d - d2) % MD;
						jj2[i] = j;
					}
					break;
				}
			}
			j = i;
		}
		if (sum < 0)
			sum += MD;
		printf("%d\n", sum);
	}
	return 0;
}

Compilation message (stderr)

arboras.c: In function 'append':
arboras.c:15:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   15 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
arboras.c: In function 'main':
arboras.c:169:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  169 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
arboras.c:173:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  173 |   scanf("%d", &pp[j]);
      |   ^~~~~~~~~~~~~~~~~~~
arboras.c:177:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  177 |   scanf("%d", &ww[j]);
      |   ^~~~~~~~~~~~~~~~~~~
arboras.c:187:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  187 |  scanf("%d", &q);
      |  ^~~~~~~~~~~~~~~
arboras.c:193:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  193 |   scanf("%d%d", &j, &w);
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 31 / 31
• Subtask 4: 45 / 45