题解连接：

https://acmer.blog.csdn.net/article/details/123555722

分类讨论情况

#include<bits/stdc++.h>
using namespace std;
char time1[100005];
int main()
{
	std::ios::sync_with_stdio(false);
	int a=0,b=0,c=0,d=0;
	cin>>time1;
	d=time1[strlen(time1)-1]-'0';
	if(time1[1]!=':'){
		a=time1[0]-'0';
		b=time1[1]-'0';
		if(time1[4]!='\0')
			c=time1[3]-'0';
	}
	else{
		b=time1[0]-'0';
		if(time1[3]!='\0')
			c=time1[2]-'0';
	}
	if(b>=6||(b==5&&c*10+d>b*10+a))
	{
		if(a==0)
			cout<<(10-b)*60-c*10-d+1;
		else
			cout<<(20-a*10-b)*60-c*10-d+2;
	}else if(a==2&&b==3&&c*10+d>b*10+a)
		cout<<60-c*10-d;
	else{
		if(c*10+d<b*10+a)
			cout<<b*10+a-c*10-d;
		else if(c*10+d==b*10+a)
			cout<<0;
		else
			cout<<60+(b+1)*10+a-c*10-d;
	}
	return 0;
}