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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main() {
  5.     ios::sync_with_stdio(false);
  6.     cin.tie(nullptr);
  7.  
  8.     int testCases;
  9.     cin >> testCases;
  10.  
  11.     while (testCases--) {
  12.         int n;
  13.         cin >> n;
  14.  
  15.         vector<int> arr(n + 1);
  16.         for (int i = 1; i <= n; i++) cin >> arr[i];
  17.  
  18.         vector<int> prefixXor(n + 1, 0);
  19.         for (int i = 1; i <= n; i++) {
  20.             prefixXor[i] = prefixXor[i - 1] ^ arr[i];
  21.         }
  22.  
  23.         vector<int> leftZeroXorCount(n + 1, 0);
  24.         vector<int> rightZeroXorCount(n + 1, 0);
  25.  
  26.         int currentXor = 0;
  27.         unordered_map<int, int> xorFrequency;
  28.         xorFrequency[currentXor] = 1;
  29.  
  30.         long long totalZeroXorSubarrays = 0;
  31.  
  32.         for (int i = 1; i <= n; i++) {
  33.             currentXor ^= arr[i];
  34.             totalZeroXorSubarrays += xorFrequency[currentXor];
  35.             xorFrequency[currentXor]++;
  36.         }
  37.  
  38.         for (int i = 1; i <= n; i++) {
  39.             int count = 0;
  40.             for (int l = 1; l <= i; l++) {
  41.                 if ((prefixXor[i] ^ prefixXor[l - 1]) == 0) {
  42.                     count++;
  43.                 }
  44.             }
  45.             leftZeroXorCount[i] = count;
  46.         }
  47.  
  48.         for (int i = n; i >= 1; i--) {
  49.             int count = 0;
  50.             for (int r = i; r <= n; r++) {
  51.                 if ((prefixXor[r] ^ prefixXor[i - 1]) == 0) {
  52.                     count++;
  53.                 }
  54.             }
  55.             rightZeroXorCount[i] = count;
  56.         }
  57.  
  58.         for (int i = 1; i < n; i++) {
  59.             totalZeroXorSubarrays += (long long)leftZeroXorCount[i] * rightZeroXorCount[i + 1];
  60.         }
  61.  
  62.         long long totalTriplets = (1LL * n * (n + 1) * (n + 2)) / 6;
  63.  
  64.         long long result = totalTriplets - totalZeroXorSubarrays;
  65.  
  66.         cout << result << "\n";
  67.     }
  68.  
  69.     return 0;
  70. }
  71.  
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin
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6
2
1 1
1 1
2
4 8
1 1
5
1 1 727 1 1
1 1 1 1 1
2
3 11
1 1
3
2 7 11
1 1 1
3
7 12 13
1 1 1
stdout
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3
1
4
1
33
1
https://ideone.com/zFTlka
language:
C++ (gcc 8.3)
created:
12 days ago
visibility:
public

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