Language: C++

#include<bits/stdc++.h>
#define all(x) (x).begin(),(x).end()
typedef long long ll;
#define rep(i,n) for(ll i=0, i##_len=(n); i<i##_len; ++i)
#define REP(i,num,n) for(ll i=num, i##_len=(n); i<i##_len; ++i)
#define repprev(i,a,b) for(ll i=b-1;i>=a;i--)
#define reprev(i,n) repprev(i,0,n)
using namespace std;
#define sz(x) ((int)(x).size())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define MEMSET(v, h) memset((v), h, sizeof(v))
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define pb push_back
#define mp make_pair
#define y0 y3487465
#define y1 y8687969
#define j0 j1347829
#define j1 j234892
#define BIT_FLAG_0 (1<<0) // 0000 0000 0000 0001
#define BIT_FLAG_1 (1<<1) // 0000 0000 0000 0010
#define BIT_FLAG_2 (1<<2) // 0000 0000 0000 0100
#define BIT_FLAG_3 (1<<3) // 0000 0000 0000 1000
#define BIT_FLAG_4 (1<<4) // 0000 0000 0001 0000
#define BIT_FLAG_5 (1<<5) // 0000 0000 0010 0000
#define BIT_FLAG_6 (1<<6) // 0000 0000 0100 0000
#define BIT_FLAG_7 (1<<7) // 0000 0000 1000 0000
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
const ll INF = 1LL<<60;

const int MAX = 510000;
const int MOD = 1000000007;

long long fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

// 二項係数計算
long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

template<class Abel> struct UnionFind {
    const Abel UNITY_SUM = 0;      // to be set
    vector<ll> par;
    vector<Abel> diff_weight;

    UnionFind(ll n) : par(n, -1), diff_weight(n, UNITY_SUM) {}
    void init(ll n) { par.assign(n, -1), diff_weight.assign(n, UNITY_SUM); }

    ll root(ll x) {
        if (par[x] < 0) return x;
        else {
            ll r = root(par[x]);
            diff_weight[x] += diff_weight[par[x]];
            return par[x] = r;
        }
    }

    Abel calc_weight(ll x) {
        root(x);
        return diff_weight[x];
    }

    bool issame(ll x, ll y) {
        return root(x) == root(y);
    }

    bool merge(ll x, ll y, Abel w = 0) {
        w += calc_weight(x); w -= calc_weight(y);
        x = root(x); y = root(y);
        if (x == y) return false;
        if (par[x] > par[y]) swap(x, y), w = -w; // merge technique
        par[x] += par[y];
        par[y] = x;
        diff_weight[y] = w;
        return true;
    }

    Abel diff(ll x, ll y) {
        return calc_weight(y) - calc_weight(x);
    }

    ll size(ll x) {
        return -par[root(x)];
    }
};

int main(){
    ll n;
  	cin >> n;
  	vector<ll> a(n);
  	rep(i,n) cin >> a[i];
    ll right = 0;
  	ll sum = 0;
    for (ll left = 0; left < n; ++left) {
        while (right < n && (sum ^ a[right]) != (sum + a[right])) {
            sum += a[right];
            ++right;
        }
    ans += (right - left);
    if (right == left) ++right;
    	else sum -= a[left];
    }
  cout << ans << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:114:5: error: 'ans' was not declared in this scope; did you mean 'abs'?
  114 |     ans += (right - left);
      |     ^~~
      |     abs
a.cc:118:11: error: 'ans' was not declared in this scope; did you mean 'abs'?
  118 |   cout << ans << endl;
      |           ^~~
      |           abs