HDU4510

水题。。。。

不过记得一圈是12小时，也就是大于12之后要mod掉12

#include<stdio.h>

int main(){
	int n;
	scanf("%d", &n);
	while (n--){
		int a, b, c, d, e, f; 
		char ch1, ch2;
		scanf("%d%c%d%c%d %d%c%d%c%d", &a, &ch1, &b, &ch1, &c, &d, &ch2, &e, &ch2, &f);	
		if (c < f){	
			c = c + 60 - f;	
			if (b == 0){
				b = 59;
				a--;	
			}
			else	
				b--;	
		}	
		else
			c = c - f;
		
		if (b < e){
			b = b + 60 - e;	
			if (a == 0)	
				a = 11;	
			else		
				a--;	
		}	
		else
			b = b - e;
		
		if (d >= 12){	
			d = d % 12;
		}
		if (d > a){	
			int t = d - a;	
			a = 12 - t;	
		}	
		else
			a = a - d;	
		printf("%.2d:%.2d:%.2d\n", a, b, c);	
	}
	return 0;
}