在数组中找到与给定总和的配对详解编程语言

 1 #include <stdio.h> 
 2 #include <stdlib.h> 
 3  
 4 //使用给定的和找到一个数组中的一对的原始方法 
 5 void findPair(int arr[], int n, int sum) 
 6 { 
 7     for (int i = 0; i < n - 1; i++) 
 8     { 
 9         for (int j = i + 1; j < n; j++) 
10         { 
11             // 找到这样的对，打印并返回 
12             if (arr[i] + arr[j] == sum) 
13             { 
14                 printf("Pair found at index %d and %d", i, j); 
15                 return; 
16             } 
17         } 
18     } 
19  
20     //在数组中不存在给定和的对 
21     printf("Pair not found"); 
22 } 
23  
24 int main() 
25 { 
26     int arr[] = { 8, 7, 2, 5, 3, 1 }; 
27     int sum = 10; 
28  
29     int n = sizeof(arr) / sizeof(arr[0]); 
30     //printf("%d/n",n); 
31  
32     findPair(arr, n, sum); 
33  
34     system("pause"); 
35     return 0; 
36 }

 1 package 排列; 
 2  
 3 public class FindPair{ 
 4     public static void findPair(int arr[], int sum){ 
 5         int n = arr.length; 
 6  
 7         for (int i = 0; i < n - 1; i++){ 
 8              
 9             for (int j = i + 1; j < n; j++){ 
10                  
11                 if (arr[i] + arr[j] == sum){ 
12                     System.out.println("Pair found at index " + i + " and " + j); 
13                     return; 
14                 } 
15             } 
16         } 
17          
18         System.out.println("Pair not found"); 
19     } 
20  
21  
22     public static void main (String[] args) 
23     { 
24         int arr[] = { 8, 7, 2, 5, 3, 1 }; 
25         int sum = 10; 
26            
27         findPair(arr, sum); 
28     } 
29 }

 1 #include <bits/stdc++.h> 
 2 using namespace std; 
 3  
 4 //使用排序在给定的数组中找到一个数组的函数 
 5 void findPair(int arr[], int n, int sum) 
 6 { 
 7     //升序排序 
 8     sort(arr, arr + n); 
 9  
10     //维护指向数组终点的两个索引 
11     int low = 0; 
12     int high = n - 1; 
13  
14     //在循环的每次迭代中减少搜索空间arr [low..high] 
15     //循环直到低小于高 
16     while (low < high) 
17     { 
18         if (arr[low] + arr[high] == sum) 
19         { 
20             cout << "Pair found "; 
21             return; 
22         } 
23  
24         //如果total小于期望的总和，则递增低索引 
25         //递减高指数是总和多于总和 
26         (arr[low] + arr[high] < sum) ? low++ : high--; 
27     } 
28  
29     cout << "Pair not found"; 
30 } 
31  
32 int main() 
33 { 
34     int arr[] = { 8, 7, 2, 5, 3, 1 }; 
35     int sum = 10; 
36  
37     int n = sizeof(arr) / sizeof(arr[0]); 
38  
39     findPair(arr, n, sum); 
40  
41     system("pause"); 
42     return 0; 
43 }

 1 package 排列; 
 2  
 3 import java.util.Arrays; 
 4  
 5 public class FindPair2 
 6 { 
 7     public static void findPair(int arr[], int sum) 
 8     { 
 9         Arrays.sort(arr); 
10  
11         int low = 0; 
12         int high = arr.length - 1; 
13       
15         while (low < high) 
16         { 
17             if (arr[low] + arr[high] == sum) 
18             { 
19                 System.out.println("Pair found"); 
20                 return; 
21             } 
22       
23             if (arr[low] + arr[high] < sum) 
24                 low++; 
25             else 
26                 high--; 
27         } 
28       
29         System.out.println("Pair not found"); 
30     } 
31  
32     public static void main (String[] args) 
33     { 
34         int arr[] = { 8, 7, 2, 5, 3, 1 }; 
35         int sum = 10; 
36            
37         findPair(arr, sum); 
38     } 
39 }

 1 #include <bits/stdc++.h> 
 2 using namespace std; 
 3  
 4 // 使用散列map 
 5 void findPair(int arr[], int n, int sum) 
 6 { 
 7     unordered_map<int, int> map; 
 8  
 9     for (int i = 0; i < n; i++) 
10     { 
11         //检查对（arr [i]，sum-arr [i]）是否存在 
12  
13         //如果差异见于之前，打印对 
14         if (map.find(sum - arr[i]) != map.end()) 
15         { 
16             cout << "Pair found at index " << map[sum - arr[i]] << " and " << i; 
17             return; 
18         } 
19  
20         //在map中存储当前元素的索引 
21         map[arr[i]] = i; 
22     } 
23  
24     cout << "Pair not found"; 
25 } 
26  
27 int main() 
28 { 
29     int arr[] = { 8, 7, 2, 5, 3, 1 }; 
30     int sum = 10; 
31  
32     int n = sizeof(arr) / sizeof(arr[0]); 
33  
34     findPair(arr, n, sum); 
35  
36     system("pause"); 
37     return 0; 
38 }

 1 package 排列; 
 2  
 3 import java.util.HashMap; 
 4 import java.util.Map; 
 5  
 6 public class FindPair3 
 7 { 
 8     public static void findPair(int arr[], int sum) 
 9     { 
10         Map<Integer, Integer> map = new HashMap<Integer, Integer>(); 
11       
12         for (int i = 0; i < arr.length; i++) 
13         { 
14       
15             if (map.containsKey(sum - arr[i])) 
16             { 
17                 System.out.println("Pair found at index " +  
18                         map.get(sum - arr[i]) + " and " + i); 
19                 return; 
20             } 
21       
22             map.put(arr[i], i); 
23         } 
24  
25         System.out.println("Pair not found"); 
26     } 
27  
28     public static void main (String[] args) 
29     { 
30         int arr[] = { 8, 7, 2, 5, 3, 1 }; 
31         int sum = 10; 
32            
33         findPair(arr, sum); 
34     } 
35 }