在一个数组 nums 中除一个数字只出现一次之外,其他数字都出现了三次。请找出那个只出现一次的数字。
示例 1:
输入:nums = [3,4,3,3]
输出:4
示例 2:
输入:nums = [9,1,7,9,7,9,7]
输出:1
限制:
1 <= nums.length <= 10000
1 <= nums[i] < 2^31
java
class Solution {
public int singleNumber(int[] nums) {
int[] count=new int[32];
for(int num:nums){
for(int i =0;i<32;i++){
count[i]+=num&1;
num>>>=1;
}
}
int res=0;
for(int i = 0;i<32;i++){
res<<=1;
res|=count[31-i]%3;
}
System.gc();
return res;
}
}
python
class Solution(object):
def singleNumber(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
count,res= [0] * 32,0
for num in nums:
for i in range(32):
count[i]+=num&1
num>>=1
for i in range(32):
res<<=1
res|=count[31-i]%3
return res if count[31] % 3 == 0 else ~(res ^ 0xffffffff)