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#include 
   
    using namespace std;typedef long long ll;const int N = 1e6 + 10;int n, res, K;int a[N], b[N];void merge(int l, int r) {       if (l >= r) return;        int mid = l + r >> 1;    merge(l, mid);    merge(mid + 1, r);        int i = l, j = mid + 1, k = l;    while (i <= mid && j <= r) {           if (a[i] <= a[j]) {               b[k++] = a[i++];        } else {               b[k++] = a[j++];            res += mid - i + 1;//统计答案        }        while (i <= mid)b[k++] = a[i++];        while (j <= r)b[k++] = a[j++];        for (int i = l; i <= r; i++) {               a[i] = b[i];        }    }}int main() {       ios::sync_with_stdio(0);    cin >> n;    for (int i = 1; i <= n; ++i) {           cin >> a[i];    }    merge(1, n);    cout << res << endl;    return 0;}
   

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