震惊cin.getline()

为什么在洛谷平台上cin.getline()会读入一个\n到字符串里，本地就不会

不把len-1就会全WA

#include<iostream>
#include<cstdio> 
#include<cstring>
using namespace std;
int n;
char last;
char s[1000];
int calc(char* x,int len){
    int js=0;
    for(int i=0;i<len;i++)
        if(x[i]==' ')js++;
    return js;
}
int calc_1(char *x,int len){
    for(int i=0;i<len;i++)
        if(x[i]==' ')return i;
}
int calc_2(char *x,int len){
    for(int i=2;i<len;i++)
        if(x[i]==' ')return i;
}
int transform(char *x,int start,int end){
    int ans1=0;
    for(int i=start;i<=end;i++)
        ans1=ans1*10+x[i]-'0';
    return ans1;
}
int calc_len(int x){
    int ans=0;
    if(x==0)return 1;
    if(x<0){
        ans=1;
        x=-x;
    }
    while(x!=0){
        x=x/10;
        ans++;
    }
    return ans;
}
int main(){
    cin.getline(s,1000);
    int l=strlen(s);
    n=transform(s,0,l-2);
    for(int i=0;i<n;i++){
       cin.getline(s,1000);
        int len=strlen(s)-1;
        int judge=calc(s,len);
        if(judge==1){
            int pos=calc_1(s,len);
            int first=transform(s,0,pos-1);
            int second=transform(s,pos+1,len-1);
            int ans=0;
            if(last=='a'){
                ans=first+second;
                cout<<first<<"+"<<second<<"="<<ans<<endl;
            }
            if(last=='b'){
                ans=first-second;
                cout<<first<<"-"<<second<<"="<<ans<<endl;
            }
            if(last=='c'){
                ans=first*second;
                cout<<first<<"*"<<second<<"="<<ans<<endl;
            }
            cout<<len+1+calc_len(ans)<<endl;
        }
        if(judge==2){
            last=s[0];
            int pos=calc_2(s,len);
            int first=transform(s,2,pos-1);
            int second=transform(s,pos+1,len-1);
            int ans=0;
            if(s[0]=='a'){
                ans=first+second;
                cout<<first<<"+"<<second<<"="<<ans<<endl;
            }
            if(s[0]=='b'){
                ans=first-second;
                cout<<first<<"-"<<second<<"="<<ans<<endl;
            }
            if(s[0]=='c'){
                ans=first*second;
                cout<<first<<"*"<<second<<"="<<ans<<endl;
            }
            cout<<len-1+calc_len(ans)<<endl;
        }       
    }
    return 0;
}