leetcode1014

这道题暴力算法，会超时：

 class Solution(object):
     def maxScoreSightseeingPair(self, A: 'List[int]') -> int:
         n = len(A)
         maxsum = 0
         for i in range(n):
             for j in range(i+1,n):
                 cursum = A[i] + A[j] + i - j
                 maxsum = max(maxsum,cursum)
         return maxsum

因此，需要使用动态规划解决：

 class Solution(object):
     def maxScoreSightseeingPair(self, A: 'List[int]') -> int:
         n = len(A)
         ans = 0
         pre = A[0]
         for i in range(1,n):
             pre = max(pre,A[i-1]+i-1)
             ans = max(ans,A[i]+pre-i)
         return ans

参考：https://leetcode.com/problems/best-sightseeing-pair/discuss/261041/easy-understand-one-pass-answer-by