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Problem solution · Go

Codeforces 1702F — Equate Multisets

Codeforces 1702F — Equate Multisets: a Go solution using direct simulation. Learn the idea, check the complexity, and read the full code, with credit to EndlessCheng Codeforces Go.

Technique
Direct simulation
Source
EndlessCheng Codeforces Go
Length
168 lines
Start with the idea.

Try the problem first. If you get stuck, read the approach below, then write your own solution. The full code is at the bottom.

Approach

Direct simulation

For Codeforces 1702F — Equate Multisets, the implementation follows the problem’s operations directly while maintaining only the state needed for the next decision.

  1. Translate each rule into one explicit state update.
  2. Maintain the invariant after every processed item.
  3. Return the accumulated state once all relevant input has been handled.

Code notes

  • 168 lines of Go from the credited upstream file 1702F.go.
  • The implementation keeps its working state in language-native values and containers.
  • No explicit loop blocks detected.

Complexity

Count the number and nesting of passes over the input, then include the maintained containers in the memory estimate.

Check the problem constraints before deciding whether this complexity will pass.

Source

Code and credit

This code comes from EndlessCheng Codeforces Go by Σndless (EndlessCheng) and is used under the MIT licence.

Open problem ↗Original source ↗
Full codeCodeforces 1702F — Equate Multisets · GoGo
Use this to learn the idea, then write your own version.
package main import (	"bufio"	. "fmt"	"io"	"math/bits"	"time") // https://space.bilibili.com/206214type node02 struct {	lr       [2]*node02	priority uint	key      int	keyCnt   int	subCnt   int} func (o *node02) size() int {	if o != nil {		return o.subCnt	}	return 0} func (o *node02) maintain() {	o.subCnt = o.keyCnt + o.lr[0].size() + o.lr[1].size()} func (o *node02) rotate(d int) *node02 {	x := o.lr[d^1]	o.lr[d^1] = x.lr[d]	x.lr[d] = o	o.maintain()	x.maintain()	return x} type treap02 struct {	rd   uint	root *node02} func (t *treap02) fastRand() uint {	t.rd ^= t.rd << 13	t.rd ^= t.rd >> 17	t.rd ^= t.rd << 5	return t.rd} func (t *treap02) size() int { return t.root.size() } func (t *treap02) _put(o *node02, key, c int) *node02 {	if o == nil {		o = &node02{priority: t.fastRand(), key: key, keyCnt: c}	} else if d := o.cmp(key); d >= 0 {		o.lr[d] = t._put(o.lr[d], key, c)		if o.lr[d].priority > o.priority {			o = o.rotate(d ^ 1)		}	} else {		o.keyCnt += c	}	o.maintain()	return o} func (t *treap02) put(key, c int) { t.root = t._put(t.root, key, c) } func (t *treap02) _delete(o *node02, key, c int) *node02 {	if o == nil {		return nil	}	if d := o.cmp(key); d >= 0 {		o.lr[d] = t._delete(o.lr[d], key, c)	} else {		if o.keyCnt > c {			o.keyCnt -= c		} else {			if o.lr[1] == nil {				return o.lr[0]			}			if o.lr[0] == nil {				return o.lr[1]			}			d = 0			if o.lr[0].priority > o.lr[1].priority {				d = 1			}			o = o.rotate(d)			o.lr[d] = t._delete(o.lr[d], key, c)		}	}	o.maintain()	return o} func (t *treap02) delete(key, c int) { t.root = t._delete(t.root, key, c) } func newTreap() *treap02 { return &treap02{rd: uint(time.Now().UnixNano())/2 + 1} } func (o *node02) cmp(a int) int {	b := o.key	if a == b {		return -1	}	if a < b {		return 0	}	return 1} func (t *treap02) max() (max *node02) {	for o := t.root; o != nil; o = o.lr[1] {		max = o	}	return} func CF1702F(_r io.Reader, _w io.Writer) {	in := bufio.NewReader(_r)	out := bufio.NewWriter(_w)	defer out.Flush() 	var T, n, v into:	for Fscan(in, &T); T > 0; T-- {		Fscan(in, &n)		a := newTreap()		for i := 0; i < n; i++ {			Fscan(in, &v)			a.put(v>>bits.TrailingZeros(uint(v)), 1)		}		b := newTreap()		for i := 0; i < n; i++ {			Fscan(in, &v)			b.put(v>>bits.TrailingZeros(uint(v)), 1)		} 		for a.size() > 0 {			p := b.max()			q := a.max()			if p.key < q.key {				Fprintln(out, "NO")				continue o			}			if p.key == q.key {				if p.keyCnt < q.keyCnt {					Fprintln(out, "NO")					continue o				}				a.delete(q.key, q.keyCnt)				b.delete(p.key, p.keyCnt)				if p.keyCnt > q.keyCnt {					b.put(p.key>>1, p.keyCnt-q.keyCnt)				}			} else {				b.delete(p.key, p.keyCnt)				b.put(p.key>>1, p.keyCnt)			}		}		Fprintln(out, "YES")	}} //func main() { CF1702F(os.Stdin, os.Stdout) }

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