Binary Prefix Divisible By 5
找了半天规律,发现没意思。直接破解了。然后submit发现有overflow,看了下输入是个数组,那真是大。立刻想到取模。取模有分配律,对答案无影响
class Solution {
public List<Boolean> prefixesDivBy5(int[] A) {
List<Boolean> res = new ArrayList<>();
long n = 0;
for(int i : A){
n = n*2 + i; //convert int[] A to binary
n %= 5;// mod distribution law
if(n == 0)
res.add(true);
else
res.add(false);
}
return res;
}
}