leetcode375 Guess Number Higher or Lower II

思路：

dp。

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

实现：

 class Solution
 {
 public:
     int getMoneyAmount(int n)
     {
         int dp[n + ][n + ];
         memset(dp, 0x3f, sizeof dp);
         for (int i = ; i <= n; i++)
             dp[i][i] = ;
         for (int i = n - ; i >= ; i--)
         {
             for (int j = i + ; j <= n; j++)
             {
                 for (int k = i; k <= j; k++)
                 {
                     dp[i][j] = min(dp[i][j], k +
                                    max(i > k -  ?  : dp[i][k - ],
                                        k +  > j ?  : dp[k + ][j]));
                 }
             }
         }
         return dp[][n];
     }
 };

 实现2：

 class Solution
 {
 public:
     int dfs(int l, int r, vector<vector<int>> & dp)
     {
         if (l == r) return ;
         if (dp[l][r] != -) return dp[l][r];
         int ans = 0x3f3f3f3f;
         ans = min(ans, l + dfs(l + , r, dp));
         ans = min(ans, r + dfs(l, r - , dp));
         for (int i = l + ; i <= r - ; i++)
         {
             ans = min(ans, max(dfs(l, i - , dp), dfs(i + , r, dp)) + i);
         }
         return dp[l][r] = ans;
     }
     int getMoneyAmount(int n)
     {
         vector<vector<int>> dp(n + , vector<int>(n + , -));
         return dfs(, n, dp);
     }
 };