Help me in solving SWAPFLIP problem

My issue

include <stdio.h>

int main() {
// your code goes here
int t;
scanf(“%d”,&t);
for(int i=0 ; i<t ; i++)
{
int n;
scanf(“%d”,&n);
char s[n],t[n];
scanf(“%s%s”,s,t);
int sum=0,a,b;
for(int j=0 ;j <n ;j++){

        a=s[j]-'0';
        b=t[j]-'0';
       
       sum=sum+a+b;
        
    }
    
    if((sum==n)||((n==1)&&'s[0]'=='t[0]')) printf("YES\n");
    else printf("NO\n");
}

}

My code

#include <stdio.h>

int main() {
	// your code goes here
	int t;
	scanf("%d",&t);
	for(int i=0 ; i<t ; i++)
	{
	    int n; 
	    scanf("%d",&n);
	    char s[n],t[n];
	    scanf("%s%s",s,t);
	    int sum=0,a,b;
	    for(int j=0 ;j <n ;j++){
	        
	        a=s[j]-'0';
	        b=t[j]-'0';
	       
	       sum=sum+a+b;
	        
	    }
	    
	    if((sum==n)||((n==1)&&'s[0]'=='t[0]')) printf("YES\n");
	    else printf("NO\n");
	}

}


Problem Link: Swap and Flip Practice Coding Problem