本文共 1136 字,大约阅读时间需要 3 分钟。
Imagine you have a special keyboard with the following keys:
Key 1: (A): Prints one ‘A’ on screen.
Key 2: (Ctrl-A): Select the whole screen.
Key 3: (Ctrl-C): Copy selection to buffer.
Key 4: (Ctrl-V): Print buffer on screen appending it after what has already been printed.
Now, you can only press the keyboard for N times (with the above four keys), find out the maximum numbers of ‘A’ you can print on screen.
Example 1:
Input: N = 3Output: 3Explanation: We can at most get 3 A's on screen by pressing following key sequence:A, A, A
Example 2:
Input: N = 7Output: 9Explanation: We can at most get 9 A's on screen by pressing following key sequence:A, A, A, Ctrl A, Ctrl C, Ctrl V, Ctrl V
Note:
1. 1 <= N <= 50 2. Answers will be in the range of 32-bit signed integer.int maxA(int N) { if (N <= 6)return N; vector dp(N + 1, 0); for (int i = 1; i <= 6; i++)dp[i] = i; // dp[n]怎么由之前的求出来呢? // 可以是dp[0..n-1]中的一直按A或者Ctrl_V而来的 for (int i = 7; i <= N; i++){ dp[i] = dp[i - 1] + 1; for (int j = i - 3; j > 0; j--){ dp[i] = max(dp[i], dp[j] * (i - j - 1)); } } return dp[N];}
转载地址:http://xxxei.baihongyu.com/