Give a linear-time algorithm to sort the ratios of n given pairs of integers between 1 and n. I. e., we need to sort, within O(n) time, n pairs of the form (ai , bi) where 1 ≤ ai ≤ n and 1 ≤ bi ≤ n using the sort key ai bi . Prove both run-time and correctness.

Writing a modular program in visual c++. i am new to this and not sure what i am missing. i am getting the following error: baddate.cpp: in function ‘int main()’: baddate.cpp: 50: 3: error: ‘else’ without a previous ‘if’elsehere are the instructions and code: writing a modular program in c++in this lab, you add the input and output statements to a partially completed c++ program. when completed, the user should be able to enter a year, a month, and a day. the program then determines if the date is valid. valid years are those that are greater than 0, valid months include the values 1 through 12, and valid days include the values 1 through 31.notice that variables have been declared for you.write the simulated housekeeping() function that contains the prompts and input statements to retrieve a year, a month, and a day from the user.include the output statements in the simulated endofjob() function. the format of the output is as follows: month/day/year is a valid date.ormonth/day/year is an invalid date.execute the program entering the following date: month = 5, day = 32, year = 2014. record the output of this program.execute the program entering the following date: month = 9, day = 21, year = 2002. record the output of this /* program name: baddate.cppfunction: this program determines if a date entered by the user is valid.input: interactiveoutput: valid date is printed or user is alerted that an invalid date was entered*/#include bool validatedate(int, int, int); using namespace std; int main(){// declare variablesint year; int month; int day; const int min_year = 0, min_month = 1, max_month = 12, min_day = 1, max_day = 31; bool validdate = true; // this is the work of the housekeeping() method// get the year, then the month, then the daycout< < "enter the year"< > year; cout< < "enter the month"< > month; cout< < "enter the day"< > day; // this is the work of the detailloop() method// check to be sure date is validif(year < = min_year) // invalid yearvaliddate = false; else if (month < min_month || month > max_month) // invalid monthvaliddate = false; else if (day < min_day || day > max_day) // invalid dayvaliddate = false; // this is the work of the endofjob() method// test to see if date is valid and output date and whether it is valid or notif(validdate == true); {// output statementcout<