PAT乙级真题：
#include <stdio.h>
int getTime(int n){
    int count = 0;
    while(n != 1){
        if(n%2 == 0){
            n /= 2;
        }else{
            n = (3*n+1)/2;
        }
        count++;
    }
    return count;
}

int main(int argc, char** argv) {
    int n;
    scanf("%d",&n);
    n = getTime(n);
    printf("%d",n);
    return 0;
}



#include<stdio.h>
int main(){
    int n,i=0;
    scanf("%d",&n);
    while(n>1&&n<1000){
        if(n%2!=0){
            n=(3*n+1)/2;
            i++;
        }
        if(n%2==0){
            n=n/2;
            i++;
        }
    }
    printf("%d",i);
}

二楼，第二个是正确的。三楼，我知道了。