动态规划子数组系列一＞等差数列划分

题目： 

 

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解析： 

 

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代码： 

public int numberOfArithmeticSlices(int[] nums) {int n = nums.length;int[] dp = new int[n];int ret = 0;for(int i = 2; i < n; i++){dp[i] = nums[i] - nums[i-1] == nums[i-1] - nums[i-2] ? dp[i-1]+1 : 0;ret += dp[i];}return ret;}