413. 等差数列划分
dp
class Solution {
public:
int numberOfArithmeticSlices(vector<int>& A) {
int n=A.size();
vector<int>dp(n);
int res=0;
for(int i=2;i<n;i++){
if(A[i]-A[i-1]==A[i-1]-A[i-2]){
dp[i]=dp[i-1]+1;
res+=dp[i];
}
}
return res;
}
};
