Help me in solving SC31 problem

help
,
1

My issue

why this approach is not working
need help to understand

My code

#include <stdio.h>

int main(void) {
	// your code goes here
	int test;
	scanf("%d",&test);
	for(int i=0;i<test;i++){
	    long long int N;
	    scanf("%lld",&N);
	    char arr[N][10];
	    getchar();
	    for(int i=0;i<N;i++){
	        scanf("%s",&arr[i]);
	       // printf("%s\n",arr[i]);
	    }
	    int max=0;
	    int weapon[10]={0};
	    for(int j=0;j<10;j++){
	        for(int i=0;i<N;i++){
	            if(arr[i][j]=='1'){
	                weapon[j]++;
	        }
	       
	    }
	    //printf("%d ",weapon[j]);
	    if((weapon[j]%2)!=0){
	        max++;
	    }
	    }
	    printf("%d\n",max);
	}
	return 0;
}

Problem Link: SC31 Problem - CodeChef