[ACM 1280]码农总共睡了多少小时？

#include<algorithm>
#include<iostream>
#include<string>
#include<vector>
using namespace std;



int main()
{
  string s1,s2;
  while(cin>>s1>>s2)
  {
    int h1 = (s1[0]-‘0‘)*10+(s1[1]-‘0‘);
    int h2 = (s2[0]-‘0‘)*10+(s2[1]-‘0‘);
    int m1 =  (s1[3]-‘0‘)*10+(s1[4]-‘0‘);
    int m2 =  (s2[3]-‘0‘)*10+(s2[4]-‘0‘);
    int flag =0;//有没有向小时借位
    int sum=0;
    if(m1>m2)
    {
      flag = 1;
      sum += (m2 +60 -m1);
    
    }
    else
    {
      sum += (m2 -m1);
    }
  
    if(h2>=(h1+flag))//等于号不要忘了哦，临界判断要谨慎
    {
    
      sum += ((h2-h1-flag)*60);
    
    }
    else
    {
      sum += ((h2+24-h1-flag)*60);
    
    }
  
    cout<<sum<<endl;
  
  
  }
}