UVa 11650 - Mirror Clock

#include <bits/stdc++.h>
using namespace std;

int main()
{
    int T,h,m,ans;

    cin>>T;

    while(T--)
    {
        scanf("%d:%d", &h, &m);

        int tt = h*60 + m;

        ans = 1440 - tt;
        ans %= 720; /// its a 12 hr clock so, mod by 720

        int hh = ans/60, mm = ans%60;
        if(hh == 0) hh+=12;   /// bcoz of 12 hr clock , we dont' have any 0 hour.. we've 12 hr so..

        printf("%02d:%02d\n", hh, mm);
    }
    return 0;
}