LeetCode 1588 Sum of All Odd Length Subarrays 前缀和
作者：互联网
Given an array of positive integers arr, return the sum of all possible odd-length subarrays of arr.
A subarray is a contiguous subsequence of the array.
Solution
求所有奇数长度子序列的和。所以维护一个前缀和以后，我们只需要遍历间隔即可
点击查看代码
class Solution {
private:
int pref[102];
int sft[102];
int ans=0;
public:
int sumOddLengthSubarrays(vector<int>& arr) {
int n = arr.size();
for(int i=0;i<n;i++)sft[i+1]=arr[i];
for(int i=1;i<=n;i++)pref[i]=pref[i-1]+sft[i];
ans+=pref[n];
int gap = 3;
while(n>=gap){
for(int i=gap;i<=n;i++){
ans+= pref[i]-pref[i-gap];
}
gap+=2;
}
return ans;
}
};
标签：1588,int,Subarrays,Sum,arr,Solution,102,array,gap 来源： https://www.cnblogs.com/xinyu04/p/16697323.html