嵌套用于同一集合上的循环，从所述集合中移除元素

我正在编写一个程序，在从一组集合中删除一个集合时遇到了一个问题。

问题

首先，我将概述所需的功能。

给定一组存储整数值的集合，例如：

[[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]] 

以及以下形式的约束列表：

((1, 2), (9, 10), (2, 9))

对于每个约束，我都在迭代集合，并根据约束合并和删除集合。例如（1，2）意味着1和2应该在同一集合中，因此合并集合。

在迭代约束之后，剩下的集合应该是：

[[1,2,9,10], [3], [4], [5], [6], [7], [8]]

当集合中只有一个元素（至少是我识别的模式）时，我实现、合并和删除集合的方法就可以了。约束按顺序迭代，在应用最终约束之前，集合的状态如下：

[[1,2], [3], [4], [5], [6], [7], [8], [9,10]]

在应用最终约束（2,9）时，这意味着包含2和9的集合应该合并，代码产生以下输出：

[[1,2,9,10], [3], [4], [5], [6], [7], [8], [9,10]]

实施

以下示例程序演示了这一点：

import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
public class SetTest {
public static void main(String[] args) {
    Set<Set<Integer>> originalSet = new HashSet<Set<Integer>>();
    Set<Integer> tempSet = new HashSet<Integer>();
    //Populate original set with sets of integers 1-10
    for (int i = 1; i <= 10; i++) {
        tempSet.add(i);
        originalSet.add(new HashSet<Integer>(tempSet));
        tempSet.clear();
    }
    System.out.println("Original Sets: ");
    for (Set<Integer> set : originalSet) {
        System.out.println(set.toString());
    }
    //Generate constraints
    List<Pair> pairSet = new LinkedList<Pair>();
    pairSet.add(new Pair(1, 2));
    pairSet.add(new Pair(9, 10));
    pairSet.add(new Pair(2, 9));
    System.out.println("Set of Pairs: ");
    for (Pair p : pairSet) {
        System.out.println(p.toString());
    }
    System.out.println("Merge and Remove Process");
    //For each pair
    for (Pair p : pairSet) {
        System.out.println("Iteration::Merge sets containing " + p.toString());
        boolean merged = false;
        //Iterate over each set in the original set
        for (Set s : originalSet) {
            //If the set contains the first element of the pair and no merge has been performed
            if (s.contains(p.getFirst()) && (merged == false)) {
                //Find the set containing the second element of the pair 
                for (Set t : originalSet) {
                    if (t.contains(p.getSecond())) {
                        //Merge t with s
                        s.addAll(t);
                        originalSet.remove(t);
                        break;
                    }
                }
                //s.add(constraint.getB());
                merged = true;
                break;
            }
            //If the set contains the second element of the pair and no merge has been performed
            if (s.contains(p.getSecond()) && (merged == false)) {
                //Find the set containing the first element of the pair 
                for (Set t : originalSet) {
                    if (t.contains(p.getFirst())) {
                        //Merge t with s
                        s.addAll(t);
                        originalSet.remove(t);
                        break;
                    }
                }
                //s.add(constraint.getB());
                merged = true;
                break;
            }
        }
        //Output the set after update
        for (Set<Integer> set : originalSet) {
            System.out.println(set.toString());
        }
    }
}
public static class Pair<F, S> {
    private F first; //first member of pair
    private S second; //second member of pair
    public Pair(F first, S second) {
        this.first = first;
        this.second = second;
    }
    public void setFirst(F first) {
        this.first = first;
    }
    public void setSecond(S second) {
        this.second = second;
    }
    public F getFirst() {
        return first;
    }
    public S getSecond() {
        return second;
    }
    @Override
    public String toString() {
        return "(" + getFirst() + ", " + getSecond() + ")";
    }
}
}

移除集合的函数在for循环中似乎不起作用，我不知道为什么。

for (Pair p : pairSet) {
        for (Set s : originalSet) {
                for (Set t : originalSet) {
                   originalSet.remove(t);
                }
        }
}

尽管合并看起来很好。

程序的输出如下：

Original Sets: 
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
Set of Pairs: 
(1, 2)
(9, 10)
(2, 9)
Merge and Remove Process
Iteration::Merge sets containing (1, 2)
[1, 2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
Iteration::Merge sets containing (9, 10)
[1, 2]
[3]
[4]
[5]
[6]
[7]
[8]
[9, 10]
Iteration::Merge sets containing (2, 9)
[1, 2, 9, 10]
[3]
[4]
[5]
[6]
[7]
[8]
[9, 10]

最后一盘[9，10]不应该存在。我很感激您能帮助我理解为什么remove函数没有达到所需的输出！

package setproblem;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
public class SetProblem {
public static void main(String[] args) {
Set<Set<Integer>> originalSet = new HashSet<Set<Integer>>();
Set<Integer> tempSet = new HashSet<Integer>();
//Populate original set with sets of integers 1-10
for (int i = 1; i <= 10; i++) {
    tempSet.add(i);
    originalSet.add(new HashSet<Integer>(tempSet));
    tempSet.clear();
}
System.out.println("Original Sets: ");
for (Set<Integer> set : originalSet) {
    System.out.println(set.toString());
}
//Generate constraints
List<Pair> pairSet = new LinkedList<Pair>();
pairSet.add(new Pair(1, 2));
pairSet.add(new Pair(9, 10));
pairSet.add(new Pair(2, 9));
System.out.println("Set of Pairs: ");
for (Pair p : pairSet) {
    System.out.println(p.toString());
}
System.out.println("Merge and Remove Process");
//For each pair
for (Pair p : pairSet) {
    System.out.println("Iteration::" + p.toString());
    Set<Integer> firstElementSet = getAllElementsFromOriginalSetContaining((Integer)p.getFirst(), originalSet);
    System.out.println("FES::" + firstElementSet.toString());
    Set<Integer> secondElementSet = getAllElementsFromOriginalSetContaining((Integer)p.getSecond(), originalSet);
    System.out.println("SES::" + secondElementSet.toString());
    removeElements(firstElementSet, originalSet);
    removeElements(secondElementSet, originalSet);
    originalSet.removeAll(firstElementSet);
    originalSet.removeAll(secondElementSet);
    firstElementSet.addAll(secondElementSet);
    originalSet.add(firstElementSet);

    for(Set<Integer> s : originalSet){
        System.out.println(s.toString());
    }
}
}
private static Set<Integer> getAllElementsFromOriginalSetContaining(Integer element, Set<Set<Integer>> originalSet) {
    Set<Integer> tempSet = new HashSet<Integer>();
    for(Set<Integer> s : originalSet){
        if(s.contains(element)){
            tempSet.addAll(s);
        }
    }
    return new HashSet<Integer>(tempSet);
}
private static void removeElements(Set<Integer> elementSet, Set<Set<Integer>> originalSet) {
    Iterator originalSetIterator = originalSet.iterator();
    while(originalSetIterator.hasNext()) {
        Set<Integer> s = (HashSet<Integer>)originalSetIterator.next();
        if(s.equals(elementSet)){
             System.out.println("Found set! " + elementSet.toString());
              System.out.println("Found in originalSet! " + s.toString());
              originalSetIterator.remove();
        }
    }        
}
public static class Pair<F, S> {
private F first; //first member of pair
private S second; //second member of pair
public Pair(F first, S second) {
    this.first = first;
    this.second = second;
}
public void setFirst(F first) {
    this.first = first;
}
public void setSecond(S second) {
    this.second = second;
}
public F getFirst() {
    return first;
}
public S getSecond() {
    return second;
}
@Override
public String toString() {
    return "(" + getFirst() + ", " + getSecond() + ")";
}
}
}

for (Set t : originalSet) {
    if (t.contains(p.getFirst())) {
        //Merge t with s
        s.addAll(t);
        originalSet.remove(t);
        break;
    }
}