CF877E

main/800-899/877E.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"bufio"
+	. "fmt"
+	"io"
+	"math/bits"
+)
+
+// https://space.bilibili.com/206214
+type seg []struct {
+	l, r int
+	ones int
+	flip bool
+}
+
+func (t seg) maintain(o int) {
+	t[o].ones = t[o<<1].ones + t[o<<1|1].ones
+}
+
+func (t seg) doFlip(O int) {
+	o := &t[O]
+	o.ones = o.r - o.l + 1 - o.ones
+	o.flip = !o.flip
+}
+
+func (t seg) spread(o int) {
+	if t[o].flip {
+		t.doFlip(o << 1)
+		t.doFlip(o<<1 | 1)
+		t[o].flip = false
+	}
+}
+
+func (t seg) build(a []int, o, l, r int) {
+	t[o].l, t[o].r = l, r
+	if l == r {
+		t[o].ones = a[l-1]
+		return
+	}
+	m := (l + r) >> 1
+	t.build(a, o<<1, l, m)
+	t.build(a, o<<1|1, m+1, r)
+	t.maintain(o)
+}
+
+func (t seg) flip(o, l, r int) {
+	if l <= t[o].l && t[o].r <= r {
+		t.doFlip(o)
+		return
+	}
+	t.spread(o)
+	m := (t[o].l + t[o].r) >> 1
+	if l <= m {
+		t.flip(o<<1, l, r)
+	}
+	if m < r {
+		t.flip(o<<1|1, l, r)
+	}
+	t.maintain(o)
+}
+
+func (t seg) onesCount(o, l, r int) int {
+	if l <= t[o].l && t[o].r <= r {
+		return t[o].ones
+	}
+	t.spread(o)
+	m := (t[o].l + t[o].r) >> 1
+	if r <= m {
+		return t.onesCount(o<<1, l, r)
+	}
+	if m < l {
+		return t.onesCount(o<<1|1, l, r)
+	}
+	return t.onesCount(o<<1, l, r) + t.onesCount(o<<1|1, l, r)
+}
+
+func cf877E(_r io.Reader, _w io.Writer) {
+	in := bufio.NewReader(_r)
+	out := bufio.NewWriter(_w)
+	defer out.Flush()
+
+	var n, p, time, q int
+	var op string
+	Fscan(in, &n)
+	g := make([][]int, n)
+	for w := 1; w < n; w++ {
+		Fscan(in, &p)
+		g[p-1] = append(g[p-1], w)
+	}
+	a := make([]int, n)
+	for i := range a {
+		Fscan(in, &a[i])
+	}
+
+	b := make([]int, n)
+	nodes := make([]struct{ l, r int }, n)
+	var f func(int) int
+	f = func(v int) int {
+		b[time] = a[v]
+		time++
+		nodes[v].l = time
+		sz := 1
+		for _, w := range g[v] {
+			sz += f(w)
+		}
+		nodes[v].r = nodes[v].l + sz - 1
+		return sz
+	}
+	f(0)
+
+	t := make(seg, 2<<bits.Len(uint(n-1)))
+	t.build(b, 1, 1, n)
+	for Fscan(in, &q); q > 0; q-- {
+		Fscan(in, &op, &p)
+		o := nodes[p-1]
+		if op[0] == 'p' {
+			t.flip(1, o.l, o.r)
+		} else {
+			Fprintln(out, t.onesCount(1, o.l, o.r))
+		}
+	}
+}
+
+//func main() { cf877E(os.Stdin, os.Stdout) }

main/800-899/877E_test.go

@@ -0,0 +1,57 @@
+// Generated by copypasta/template/generator_test.go
+package main
+
+import (
+	"github.com/EndlessCheng/codeforces-go/main/testutil"
+	"testing"
+)
+
+// https://codeforces.com/problemset/problem/877/E
+// https://codeforces.com/problemset/status/877/problem/E
+func Test_cf877E(t *testing.T) {
+	testCases := [][2]string{
+		{
+			`4
+1 1 1
+1 0 0 1
+9
+get 1
+get 2
+get 3
+get 4
+pow 1
+get 1
+get 2
+get 3
+get 4`,
+			`2
+0
+0
+1
+2
+1
+1
+0`,
+		},
+		{
+			`10
+1 2 3 4 2 4 1 7 8
+1 1 0 1 1 0 0 0 1 1
+10
+pow 1
+get 2
+pow 2
+pow 8
+get 6
+pow 6
+pow 10
+get 6
+pow 8
+pow 3`,
+			`3
+0
+1`,
+		},
+	}
+	testutil.AssertEqualStringCase(t, testCases, 0, cf877E)
+}