Educational Codeforces Round 72 (Rated for Div. 2)

Educational Codeforces Round 72 (Rated for Div. 2)

A

# include <bits/stdc++.h>
using namespace std;
​
typedef long long LL;
int main()
{
    int T;
    scanf("%d",&T);
    while(T--){
        LL str,intt,exp;
        LL ans=0;
        scanf("%lld%lld%lld",&str,&intt,&exp);
        ans=exp+str;
        if(ans<=intt){
            ans=0;
        }else{
            ans=ans-intt;
            if(ans%2==0) ans=ans/2;
            else ans=ans/2+1;
        }   
        printf("%lld\n",ans);
        
    }
    
    return 0;
}
​

B

# include <bits/stdc++.h>
using namespace std;
​
int d[110],h[110];
int main()
{
    int t;
    scanf("%d",&t);
    while(t--){
        int n,x;
        scanf("%d%d",&n,&x);
        int dd,hh,c=0;
        int flag=0;
        for(int i=1;i<=n;i++){
            scanf("%d%d",&d[i],&h[i]);
            if(min(d[i],x)<=h[i]) continue;
            else{
                flag=1;
                int cc=d[i]-h[i];
                if(cc>c){
                    dd=d[i];
                    hh=h[i];
                    c=cc;
                } 
            }
        }
        if(flag==0){
            int ff=1;
            for(int i=1;i<=n;i++){
                if(d[i]>=x){
                    printf("1\n");
                    ff=0;
                    break;
                }
            }
            if(ff) printf("-1\n");
        }
        else{
            //cout<<"!!"<<c<<endl;
            int ans=x/c;
            int cnt=1e9;
            int y=x%c;
            if(dd%c!=y) cnt=ans+1; 
            for(int i=1;i<=n;i++){
                if(d[i]%c==y){
                    int k=d[i]/c;
                    ans=ans-k+1;
                    cnt=min(cnt,ans);
                }   
            }
            printf("%d\n",cnt);
        }
    }
    
    
    return 0;
 } 
​

D

# include <bits/stdc++.h>
using namespace std;
​
typedef long long LL;
int main()
{
    int T;
    scanf("%d",&T);
    while(T--){
        LL str,intt,exp,n;
        LL ans=0;
        scanf("%lld%lld%lld",&str,&intt,&exp);
        ans=exp+str;
        if(ans<=intt){
            ans=0;
        }else{
            ans=(ans-intt);
            if(ans%2==0) ans=ans/2;
            else ans=ans/2+1;
        }   
        printf("%lld\n",ans);
        
    }
    
    return 0;
}
​