Time Conversion-hackerrank-algorithm-solution

Given a time in -hour AM/PM format, convert it to military (-hour) time.
Note: Midnight is on a -hour clock, and on a -hour clock. Noon is on a -hour clock, and on a -hour clock.

Input Format

A single string containing a time in -hour clock format (i.e.: or ), where and .

Output Format

Convert and print the given time in -hour format, where .

Sample Input

07:05:45PM

Sample Output

19:05:45

C++ code: 

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int main(){
      string s;
    cin >> s;

    int n = s.length();
    int hh, mm, ss;
    hh = (s[0] - '0') * 10 + (s[1] - '0');
    mm = (s[3] - '0') * 10 + (s[4] - '0');
    ss = (s[6] - '0') * 10 + (s[7] - '0');

    if (hh < 12 && s[8] == 'P') hh += 12;
    if (hh == 12 && s[8] == 'A') hh = 0;

    printf("%02d:%02d:%02d\n", hh, mm, ss);

    return 0;
}