统计元素和差值为偶数的分区方案

https://leetcode.cn/problems/count-partitions-with-even-sum-difference/description/

class Solution {
public:
int countPartitions(vector& nums) {
int count=0,sum1=0;
for(auto p=nums.begin();p!=nums.end()-1;p++){
sum1+=p;
int sum=0;
for(auto q=p+1;q!=nums.end();q++){
sum+=q;
}
int s=sum1-sum;
if(s<0)s=-s;
if(s%2==0){
count++;
}
}
return count;
}
};