思路：

dp。

https://leetcode.com/problems/guess-number-higher-or-lower-ii/discuss/

實現：

 1 class Solution 
 2 {
 3 public:
 4     int getMoneyAmount(int n) 
 5     {
 6         int dp[n + 1][n + 1];
 7         memset(dp, 0x3f, sizeof dp);
 8         for (int i = 0; i <= n; i++)
 9             dp[i][i] = 0;
10         for
 
 (int i = n - 1; i >= 1; i--)
11         {
12             for (int j = i + 1; j <= n; j++)
13             {
14                 for (int k = i; k <= j; k++)
15                 {
16                     dp[i][j] = min(dp[i][j], k + 
17                                    max(i > k - 1 ? 0 : dp[i][k - 1
 
], 
18                                        k + 1 > j ? 0 : dp[k + 1][j]));
19                 }
20             }
21         }
22         return dp[1][n];
23     }
24 };

leetcode375 Guess Number Higher or Lower II