原题链接
Note:
两遍循环肯定爆时间了,那么修改一下,用前缀和来解决
每个位置分别计算和左边的绝对值差And和右边的绝对值之差
列出来之后看着图手推一下公式然后代码照着敲即可
Note:和后面就是求的Right,和前面就是求的Left
代码如下:
class Solution {
public:
vector<int> getSumAbsoluteDifferences(vector<int>& nums) {
vector<int> sum, res;
int n = nums.size();
sum.push_back(0);
for(int i = 0; i < n; i ++)
sum.push_back(sum[i] + nums[i]);
for(int i = 0; i < n; i ++)
{
int left = (i + 1) * nums[i] - sum[i + 1];
int right = sum[n] - sum[i + 1] - nums[i] * (n - i - 1);
res.push_back(left + right);
}
return res;
}
};