View Code of Problem 56

#include <stdio.h>
#include <string.h>
#include <math.h>
#define N 100000
int main()
{
	int s1,f1,m1,s2,f2,m2;
	int s,f,m;
	int sum1,sum2;
	scanf("%d:%d:%d",&s1,&f1,&m1);
	scanf("%d:%d:%d",&s2,&f2,&m2);
	sum1=s1*3600+f1*60+m1;
	sum2=s2*3600+f2*60+m2;
	if(sum1>sum2)
	{
		s=s1-s2;
		if(f1<f2)
		{
			f=f1-60;
			s-=1;
		}
		else
		{
			f=f1-f2;
		}
		if(m1<m2)
		{
			m=m1-60;
			f-=1;
		}
		else
		{
			m=m1-m2;
		}
		printf("%d:%02d:%02d\n",s,f,m);
	}
	else
	{
		s=s2-s1;
		if(f1>f2)
		{
			f=f2-60;
			s-=1;
		}
		else
		{
			f=f2-f1;
		}
		if(m1>m2)
		{
			m=m2-60;
			f-=1;
		}
		else
		{
			m=m2-m1;
		}
		printf("%d:%02d:%02d\n",s,f,m);
	}
	return 0;
}