dp of length n + 1 with all false values, and set dp[0] to true.nums using index i:
dp_index as i + 1.i > 0 and nums[i] == nums[i - 1], set dp[dp_index] to dp[dp_index] or dp[dp_index - 2].i > 1 and nums[i] == nums[i - 1] == nums[i - 2], set dp[dp_index] to dp[dp_index] or dp[dp_index - 3].i > 1 and nums[i] == nums[i - 1] + 1 and nums[i - 1] == nums[i - 2] + 1, set dp[dp_index] to dp[dp_index] or dp[dp_index - 3].dp[n].