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Problem solution · Go

Codeforces 1313B — Different Rules

Codeforces 1313B — Different Rules: 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
171 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 1313B — Different Rules, 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

  • 171 lines of Go from the credited upstream file 1313B.go.
  • The implementation visibly relies on sequence storage.
  • 1 loop block 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 1313B — Different Rules · GoGo
Use this to learn the idea, then write your own version.
package main import (	"bufio"	. "fmt"	"io") // github.com/EndlessCheng/codeforces-gofunc CF1313B(_r io.Reader, _w io.Writer) {	in := bufio.NewReader(_r)	out := bufio.NewWriter(_w)	defer out.Flush() 	solve := func() (ans1, ans2 int) {		var n, x, y int		Fscan(in, &n, &x, &y)		if x > y {			x, y = y, x		}		if y == 1 {			return 1, 1		} 		if x >= n-1 {			ans1 = y // 比赛时这里我写成了 n		} else {			if x+y < n+1 {				ans1 = 1			} else {				remove := n - x - 1				ans1 = y - remove			}		}		if x+y < n+1 {			ans2 = x + y - 1		} else {			ans2 = n		}		return	}	_ = solve 	solve2 := func() (ans1, ans2 int) {		var n, x, y int		Fscan(in, &n, &x, &y)		if x+y <= n {			return 1, x + y - 1		}		if x+y < 2*n {			return x + y - n + 1, n		}		return n, n	}	_ = solve2 	var t int	Fscan(in, &t)	for _case := 1; _case <= t; _case++ {		a, b := solve2()		Fprintln(out, a, b)	}} // 打表就行了// 2 1 1 1 1// 3 1 2 1 2// 3 2 1 1 2// 4 1 3 1 3// 4 2 2 1 3// 4 3 1 1 3// 5 1 4 1 4// 5 2 3 1 4// 5 3 2 1 4// 5 4 1 1 4// 6 1 5 2 5// 6 2 4 2 5// 6 3 3 2 5// 6 4 2 2 5// 6 5 1 2 5// 7 2 5 3 5// 7 3 4 3 5// 7 4 3 3 5// 7 5 2 3 5// 8 3 5 4 5// 8 4 4 4 5// 8 5 3 4 5// 9 4 5 5 5// 9 5 4 5 5//10 5 5 5 5func printTable(n int) {	permutations := func(n, r int, do func(indexes []int)) {		indexes := make([]int, n)		for i := range indexes {			indexes[i] = i + 1		}		do(indexes[:r])		cycles := make([]int, r)		for i := range cycles {			cycles[i] = n - i		}		for {			i := r - 1			for ; i >= 0; i-- {				cycles[i]--				if cycles[i] == 0 {					tmp := indexes[i]					copy(indexes[i:], indexes[i+1:])					indexes[n-1] = tmp					cycles[i] = n - i				} else {					j := cycles[i]					indexes[i], indexes[n-j] = indexes[n-j], indexes[i]					do(indexes[:r])					break				}			}			if i == -1 {				return			}		}	}	min := func(a, b int) int {		if a < b {			return a		}		return b	}	max := func(a, b int) int {		if a > b {			return a		}		return b	} 	getPlace := func(indexes1, indexes2 []int) (ans int) {		score := indexes1[0] + indexes2[0]		for i := 1; i < len(indexes1); i++ {			if indexes1[i]+indexes2[i] <= score {				ans++			}		}		return ans + 1	} 	for sum := 0; sum < 2*n-1; sum++ {		for x := 0; x <= sum; x++ {			y := sum - x			xx, yy := x+1, y+1			if xx > n || yy > n {				continue			}			minPlace, maxPlace := int(1e9), 0			permutations(n, n, func(indexes1 []int) {				if indexes1[0] == xx {					permutations(n, n, func(indexes2 []int) {						if indexes2[0] == yy {							p := getPlace(indexes1, indexes2)							minPlace = min(minPlace, p)							maxPlace = max(maxPlace, p)						}					})				}			})			Println(xx+yy, xx, yy, minPlace, maxPlace)		}	}} //func main() { CF1313B(os.Stdin, os.Stdout) }

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