//uva11078 #include <iostream> using namespace std; int main() { int i, times, grade_num, grade, max_grade, ans; cin >> times; while (times > 0) { cin >> grade_num; cin >> max_grade; ans = -1000000; for (i = 1; i < grade_num; i++) { cin >> grade; if (max_grade - grade > ans) ans = max_grade - grade; if (max_grade < grade) max_grade = grade; } cout << ans << endl; times--; } return 0; }