#include

int main() {

char str[30]="";

int ans=0;

int number[4]={0};

int count=0;

const char* d = " ";

char *p;

scanf("%[^\n]",str);

p = strtok(str, d);

count=0;

while (p != NULL) {

number[count++]=atoi(p);

p = strtok(NULL, d);

if (count==4)break;

}

if(number[3]-number[2]==number[2]-number[1]){

//等差

number[4]=(number[3]-number[2])+number[3];

}

else if(number[3]/number[2]==number[2]/number[1]){

//等比

number[4]=(number[3]/number[2])*number[3];

}

if(count>=4){

for(int x=0; x<=count; x++) {

printf("%d ",number[x]);

}

}else{

printf("\r");

}

//printf("%d\n",ans);

 

return 0;

}

 

輸入第一行是數列的數目