算法训练 集合运算

  1 #include<iostream>
  2 #include<vector>
  3 #include<algorithm>
  4 using namespace std;
  5 
  6 bool cmp(int a, int b)
  7 {
  8     return a < b;
  9 }
 10 
 11 int main()
 12 {
 13     int arr1Num,arr2Num;
 14     int flag = 0;
 15     
 16     cin >> arr1Num;
 17     vector<int> arr1(arr1Num);
 18      for (int i = 0; i < arr1Num; i++)
 19     {
 20         cin >> arr1[i];
 21     }
 22 
 23     cin >> arr2Num;
 24     vector<int> arr2(arr2Num);
 25     for (int i = 0; i < arr2Num; i++)
 26     {
 27         cin >> arr2[i];
 28     }
 29 
 30     //交集
 31     int b[2000] = { 0 };
 32     int l = -1;
 33     for (int i = 0; i < arr1Num; i++)
 34     {
 35         for (int j = 0; j < arr2Num; j++)
 36         {
 37             if (arr1[i] == arr2[j])
 38             {
 39                 flag = 1;  //有交集
 40                 b[++l] = arr1[i];
 41             }
 42         }
 43     }
 44     if (flag == 1)  //有交集才输出换行
 45     {
 46         sort(b, b + l + 1, cmp);
 47         for (int i = 0; i < l + 1; i++)
 48         {
 49             cout << b[i] << " ";
 50         }
 51         cout << endl;
 52     }
 53     
 54     //并集
 55     vector<int> arr3(arr1Num+arr2Num);
 56     for (int i = 0; i < arr1Num; i++) //把两个数组的数字全导入arr3中
 57     {
 58         arr3[i] = arr1[i];
 59     }
 60     for (int j = arr1Num; j < arr1Num + arr2Num; j++)
 61     {
 62         arr3[j] = arr2[j - arr1Num];
 63     }
 64     sort(arr3.begin(), arr3.end(), cmp); //从小到大排序
 65     cout << arr3[0] << " ";
 66     for (int i = 1; i < arr1Num + arr2Num; i++)
 67     {
 68         if (arr3[i] != arr3[i - 1])
 69         {
 70             cout << arr3[i] << " ";
 71         }
 72     }
 73     cout << endl;
 74 
 75     //余集
 76     int i, j,k = -1;
 77     int a[2000] = { 0 };  //先记录下来
 78     int cnt = 0;
 79     for (i = 0; i < arr1Num; i++)
 80     {
 81         for (j = 0; j < arr2Num; j++)
 82         {
 83             if (arr1[i] == arr2[j])
 84             {
 85                 break;
 86             }
 87         }
 88         if (j == arr2Num)
 89         {
 90             a[++k] = arr1[i];
 91             cnt++;
 92         }
 93     }
 94     sort(a, a + k + 1, cmp); //从小到大输出
 95     for (i = 0; i < cnt; i++)
 96     {
 97         cout << a[i] << " ";
 98     }
 99     return 0;
100 }