issue51303.go

     1  // run
     2  
     3  // Copyright 2022 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package main
     8  
     9  import (
    10  	"fmt"
    11  )
    12  
    13  func main() {
    14  	x := [][]int{{1}}
    15  	y := [][]int{{2, 3}}
    16  	IntersectSS(x, y)
    17  }
    18  
    19  type list[E any] interface {
    20  	~[]E
    21  	Equal(x, y E) bool
    22  }
    23  
    24  // ss is a set of sets
    25  type ss[E comparable, T []E] []T
    26  
    27  func (ss[E, T]) Equal(a, b T) bool {
    28  	return SetEq(a, b)
    29  }
    30  
    31  func IntersectSS[E comparable](x, y [][]E) [][]E {
    32  	return IntersectT[[]E, ss[E, []E]](ss[E, []E](x), ss[E, []E](y))
    33  }
    34  
    35  func IntersectT[E any, L list[E]](x, y L) L {
    36  	var z L
    37  outer:
    38  	for _, xe := range x {
    39  		fmt.Println("xe", xe)
    40  		for _, ye := range y {
    41  			fmt.Println("ye", ye)
    42  			fmt.Println("x", x)
    43  			if x.Equal(xe, ye) {
    44  				fmt.Println("appending")
    45  				z = append(z, xe)
    46  				continue outer
    47  			}
    48  		}
    49  	}
    50  	return z
    51  }
    52  
    53  func SetEq[S []E, E comparable](x, y S) bool {
    54  	fmt.Println("SetEq", x, y)
    55  outer:
    56  	for _, xe := range x {
    57  		for _, ye := range y {
    58  			if xe == ye {
    59  				continue outer
    60  			}
    61  		}
    62  		return false // xs wasn't found in y
    63  	}
    64  	return true
    65  }
    66
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