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  1. import java.util.*;
  2.  
  3. public class Main {
  4.     public static void main(String[] args) {
  5.         Scanner sc = new Scanner(System.in);
  6.  
  7.  
  8.         if (!sc.hasNextInt()) return;
  9.         int n = sc.nextInt();
  10.  
  11.  
  12.         int[] arr = new int[n];
  13.         for (int i = 0; i < n; i++) {
  14.             arr[i] = sc.nextInt();
  15.         }
  16.  
  17.  
  18.         int result = maxLength(arr);
  19.  
  20.  
  21.         System.out.println(result);
  22.     }
  23.  
  24.     public static int maxLength(int arr[]) {
  25.         Map<Integer, Integer> map = new HashMap<>();
  26.         int n = arr.length;
  27.         int sum = 0;
  28.         int[] prefixSum = new int[n];
  29.  
  30.         for (int i = 0; i < n; i++) {
  31.             sum += arr[i];
  32.             prefixSum[i] = sum; 
  33.         }
  34.  
  35.         int maxLongestSubArray = 0;
  36.         for (int i = 0; i < n; i++) {
  37.             int num = prefixSum[i];
  38.  
  39.             if (num == 0) {
  40.                 maxLongestSubArray = Math.max(maxLongestSubArray, i + 1);
  41.             }
  42.  
  43.             if (map.containsKey(num)) {
  44.                 int currentLongestSubArray = i - map.get(num);
  45.                 maxLongestSubArray = Math.max(currentLongestSubArray, maxLongestSubArray);
  46.             } else {
  47.                 map.put(num, i);
  48.             }
  49.         }
  50.  
  51.         return maxLongestSubArray;
  52.     }
  53. }
  54.  
Success #stdin #stdout 0.1s 54512KB
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stdout 
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https://ideone.com/5IFeqM
language:
Java (HotSpot 12)
created:
12 hours ago
visibility:
public

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