How to get test cases of questions on codestudio

Guys, in one of the question my code is passing 5/6 test cases. Is there any way that I can know that one case which my code is not able to follow.

Question - Check Permutation

https://www.codingninjas.com/codestudio/guided-paths/basics-of-c/content/118818/offering/1381766?leftPanelTab=0

// My code.
#include
#include
using namespace std;

bool isPermutation(char input1[], char input2[]) {
// Write your code here
if(strlen(input1) != strlen(input2)){
return 0;
}

for(int i = 0; i < input1[i] != 0; i++){
    int flag = 0;
    for(int j = 0; j < input2[j] != 0; j++){
        if(input1[i] == input2[j]){
            input2[j] = 'A';
            flag = 1;
            break;
        }
    }
    if(!flag){
        return 0;
    }
}
return 1;

}

int main() {
int size = 1e6;
char str1[size];
char str2[size];
cin >> str1 >> str2;
cout << (isPermutation(str1, str2) ? “true” : “false”);
}