public static String DecimaltoBinary(int num){
char[] ch = Integer.toBinaryString(num).toCharArray();
String res = "";
if(ch.length == 1 && ch[0] == '0'){
return "0";
}
//从左到右记录幂的位置
int temp = ch.length-1;
String s = "";
for (int i = 0; i < ch.length; i++) {
if (ch[i] == '1') {
if(temp > 2) {
s = DecimaltoBinary(temp);
}else{
s = temp+"";
}
if(res == "") {
res += "2(" + s + ")";
} else {
res += "+" + "2(" + s +
")";
}
}
temp--;
}
return res;
}
就一个递归调用，没有多判断负数，上面有大神已经判断了！不过没想过复杂度的问题，能力不够
