```cpp #include <bits/stdc++.h> #define inf 0x3f3f3f3f #define Linf 0x3f3f3f3f3f3f3f3f using namespace std; const int N = 5e5+2, M = 102, mod = 1e9+7; void add(int &a, int b) { if(a + b >= mod) a = a + b - mod; else if(a + b < 0) a = a + b + mod; else a = a + b; } int n, a[N]; int f[M]; int ans; signed main() { cin >> n; for(int i = 1; i <= n; ++i) scanf("%d", &a[i]); for(int d = -100; d <= 100; ++d) { memset(f, 0, sizeof(f)); for(int i = 1; i <= n; ++i) { int val = a[i] - d; if(val >= 0 && val <= 100) add(f[a[i]], f[val]); add(f[a[i]], 1); } for(int i = 0; i <= 100; ++i) add(ans, f[i]); if(d != 0) add(ans, -n); } cout << ans; return 0; } ```