Stop watch

#include<stdio.h>

int pow(int x,int up){
    if(up == 0)return 1;
    int tx = x;
    for(int i = 2 ; i <= up ; i ++){
        x*=tx;
    }
    return x;
}

int main()
{
    int T;
    scanf("%d",&T);
    for(int t = 0 ; t < T ; t ++){
        int n;
        scanf("%d",&n);
        int base = 10 - n;
        int prebase = 0;
        bool check[10];for(int i = 0 ; i < 10 ; i ++)check[i] = true;
        for(int i = 0 ; i < n ; i ++){
            int x;
            scanf("%d",&x);
            check[x] = false;
        }
        int value[10]; for(int i = 0 ; i < 10 ; i ++)value[i] = -1;
        int val = 0;
        for(int i = 0 ; i < 10 ; i++){
            if(check[i]){
                value[i] = val++;
                if(i < 6){
                    prebase ++;
                }
            }
        }

        int a,b,c;
        char ch;
        scanf("%d%c%d%c%d",&a,&ch,&b,&ch,&c);
        int sum = 0;
    //  printf("Test (%d,%d)\n",value[c/10]*pow(base,1),value[c%10]*pow(base,0));
        sum += value[c%10]*pow(base,0);
        c /= 10;
        sum += value[c]*pow(base,1);

        sum += value[b%10]*pow(base,2);
        b /= 10;
        sum += value[b]*pow(base,3);

        int sumMM = 0;
        int cnt = 0;
        while(a!=0){
            sumMM += value[a%10]*pow(base,cnt++);
            a/=10;
        }
    //  printf("%d * %d\n",sumMM,pow(base,3)*prebase);
        sum += sumMM*pow(base,3)*prebase;
    //  printf("Test sum : %d\n",sum);
        int x,y,z;
        z = sum%100;
        sum/=100;
        y = sum%60;
        sum/=60;
        x = sum;
        printf("%02d:%02d:%02d\n",x,y,z);
    }
    return 0;
}