整数分块部分：

错误代码

for (ll l = 1, r; l <= n; l = r + 1)
		{
			r = min(n, min(a / (a / l), b / (b / l)));
			ans += (ll)(s[r] - s[l - 1]) * a / l * b / l;
		}

AC代码

for (ll l = 1, r; l <= n; l = r + 1)
		{
			r = min(n, min(a / (a / l), b / (b / l)));
			ans += (ll)(s[r] - s[l - 1]) * (a / l) * (b / l);
		}