洛谷这种错误是什么意思

Wrong Answer too long 什么意思，我真的改崩溃了！谢谢大家了
CSP-S2021 回文代码如下：

#include<cstdio>
#include<cstring>
int num[1000000];
char s[1000000];
int main(){
    int tot;
    scanf("%d",&tot);
    while(tot--){
        int t;
        scanf("%d",&t);
        int sum=2*t;
        for(int i=1;i<=sum;i++){
            scanf("%d",&num[i]);
        }
        int nei;
        for(int i=2;i<=sum;i++){
            if(num[1]==num[i]){
                nei=i;
                break;
            }
        }
        int wai_left=2;
        int wai_right=sum;
        int nei_left=nei-1;
        int nei_right=nei+1;
        int start=1,end=sum;
        s[start]='L';
        s[end]='L';
        while(1){
            if(start==end-1){
                printf("%s\n",s+1);
                break;
            }
            if(num[wai_left]==num[nei_left]  && wai_left<nei_left){
                s[++start]='L';
                s[--end]='L';
                 wai_left++;
                 nei_left--;
            }
            else if(num[wai_left]==num[nei_right]){
                 s[++start]='L';
                s[--end]='R';
                 wai_left++;
                 nei_right++;
            }
            else if(num[wai_right]==num[nei_left]){
                s[++start]='R';
                s[--end]='L';
                 wai_right--;
                 nei_left--;
            }
            else if(num[wai_right]==num[nei_right]  &&  wai_right>nei_right){
                s[++start]='R';
                s[--end]='R';
                 wai_right--;
                 nei_right++;
            }
            else{
                break;
            }
        }    
        
        if(start==end-1){
            continue;
        }
        
        for(int i=1;i<sum;i++){
            if(num[sum]==num[i]){
                nei=i;
                break;
            }
        }
        wai_left=1;
        wai_right=sum-1;
        nei_left=nei-1;
        nei_right=nei+1;
        start=1,end=sum;
        s[start]='R';
        s[end]='L';
        while(1){
            if(start==end-1){
                printf("%s\n",s+1);
                break;
            }
            if(num[wai_left]==num[nei_left] && wai_left<nei_left){
                s[++start]='L';
                s[--end]='L';
                 wai_left++;
                 nei_left--;
            }
            else if(num[wai_left]==num[nei_right]){
                 s[++start]='L';
                s[--end]='R';
                 wai_left++;
                 nei_right++;
            }
            else if(num[wai_right]==num[nei_left]){
                s[++start]='R';
                s[--end]='L';
                 wai_right--;
                 nei_left--;
            }
            else if(num[wai_right]==num[nei_right] && wai_right>nei_right){
                s[++start]='R';
                s[--end]='R';
                 wai_right--;
                 nei_right++;
            }
            else{
                putchar('-');
                putchar('1');
                putchar('\n');
                break;
            }
        }            
    }
    return 0;
} 

多输出了答案