下面count_triple函数的时间复杂度为( )。
int count_triple(int n) { int cnt = 0; for (int a = 1; a <= n; a++) for (int b = a; a + b <= n; b++) { int c = sqrt(a * a + b * b); if (a + b + c > n) break; if (a * a + b * b == c * c) cnt++; } return cnt;}