利用真假选猴子大王
public class Mokey {
public static void main (String[] args){
boolean[] arr = new boolean[500];
for( int i=0; i<arr.length; i++){
arr[i] = true;
}

int len = arr.length;
int countNum = 0;
int index = 0;

while( len > 1 ){
if( arr[index] == true ){
countNum ++;
if(countNum == 3 ){ //置为false
countNum = 0;
arr[index] = false;
len --;
}
}
index++;

if( index == arr.length ) {
index=0;
}
}

for(int i=0; i<arr.length; i++){
if( arr[i]==true ){
System.out.println(i);
}
}
}
}