原題:
Given an array of integers, every element appears three times except for one. Find that single one.
Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?
class Solution {
public:
int singleNumber(int A[], int n) {
int bitnum[32] = {0};
int res = 0;
for (int i = 0; i<32; i++){
for (int j = 0; j<n; j++)
bitnum[i] += (A[j]>>i)&1;
res |= (bitnum[i]%3)<<i;
}
return res;
}
};
我本覺得res |= (bitnum[i]%3)<<i;
可以用
res =res+ (bitnum[i]%3)<<i;
代替,
或者是
bitnum[i] += (A[j]>>i)&1;
可以用
bitnum[i] = bitnum[i]+ (A[j]>>i)&1;
代替
不過全部報錯