In my opinion everything is ok but i have WA#1

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main()
{
    int n;
    int liczba, y=0, i=0, z;
    int lengthG = 0, lengthS = 0, lengthR = 0, lengthH = 0;

    char g[250000];
    char s[250000];
    char h[250000];
    char r[250000];
    char wyraz[2500];
    char szkola[2500];

    scanf("%d", &n);

    for(i=0; i<n; i++)
    {
            fflush(stdin);
            gets(wyraz);
            scanf("%2000s", szkola);

            liczba = strlen(wyraz);

            if(strcmp( szkola , "Gryffindor" ) == 0 )
            {
                         z=0;
                         for(y=lengthG; y<(liczba + lengthG); y++)
                         {
                                 g[y] = wyraz[z];
                                 z++;
                         }

                         g[lengthG+liczba] = '\n';
                         lengthG += liczba + 1;
            }

            if(strcmp( szkola , "Slytherin" ) == 0)
            {
                         z=0;
                         for(y=lengthS; y<(liczba + lengthS); y++)
                         {
                                 s[y] = wyraz[z];
                                 z++;
                         }

                         s[lengthS+liczba] = '\n';
                         lengthS += liczba + 1;
            }

            if(strcmp(szkola, "Hufflepuff") == 0)
            {
                         z=0;
                         for(y=lengthH; y<(liczba+lengthH); y++)
                         {
                                 h[y] = wyraz[z];
                                 z++;
                         }

                         h[lengthH+liczba] = '\n';
                         lengthH += liczba + 1;
            }

            if(strcmp(szkola, "Ravenclaw") == 0)
            {
                         z=0;
                         for(y=lengthR; y<(liczba+lengthR); y++)
                         {
                                 r[y] = wyraz[z];
                                 z++;
                         }

                         r[lengthR+liczba] = '\n';
                         lengthR += liczba + 1;
            }
    }

            g[lengthG] = '\0';
            r[lengthR-1] = '\0';
            s[lengthS] = '\0';
            h[lengthH] = '\0';

    printf("Slytherin:\n");
    puts(s);

    printf("Hufflepuff:\n");
    puts(h);

    printf("Gryffindor:\n");
    puts(g);

    printf("Ravenclaw:\n");
    puts(r);


}