week13- C. Become an Escapiest is not easy!, Author Solution

#include <cstdio>
const int SIZE = 1e3;
int row_st[SIZE],N;
int main(){
    scanf("%d",&N);
    printf("%d\n",N);
    int now=0;
    for(int i=0;i<N;i+=2){
        row_st[i]=now;
        now+=N;
    }
    for(int i=1;i<N;i+=2){
        row_st[i]=now;
        now+=N;
    }
    int ll=row_st[0],rr=row_st[0]+N-1;
    for(int j=0;j<N;j++){
        int v;
        if(j<3)v=ll++;
        else if(j%4!=2)v=rr--;
        else v=ll++;
        printf("%d%c",v," \n"[j==N-1]);
    }
    for(int i=1;i<N-1;i++){
        if(i%2==1){
            for(int j=0;j<N;j++)printf("%d%c",row_st[i]+j," \n"[j==N-1]);
        }
        else{
            for(int j=0;j<N;j++)printf("%d%c",row_st[i]+N-1-j," \n"[j==N-1]);
        }
    }
    ll=row_st[N-1],rr=row_st[N-1]+N-1;
    for(int j=0;j<N;j++){
        int v;
        if(j%4==1||j%4==2)v=rr--;
        else v=ll++;
        printf("%d%c",v," \n"[j==N-1]);
    }
    return 0;
}