如何使用给定的四个键打印最大数量的"A"
data structurealgorithmsdynamic programming更新于 2025/6/24 8:52:17
假设,我们将尝试使用键盘输入字母"A"。我们的目标是仅使用四个键,并尝试在文本字段中输入最大数量的"A"。这四个键分别是"A"、"C"、"V"和"Ctrl"。
为了输出最大数量的"A",我们将使用 Ctrl + A 全选,Ctrl + C 复制,Ctrl + V 粘贴。
输入和输出
Input: Number of keystrokes, say 7 Output: Maximum Number of A's with 7 keystrokes is: 9 Press A three times. Then Ctrl+A, Ctrl+C, Ctrl+V, Ctrl+V
算法
keyNumbers(keyStrokes)
输入:击键次数。
输出:使用这些击键的最大字母数。
Begin if keyStrokes <= 6, then return keyStrokes for n := 1 to 6, do result[n-1] := n done for n := 7 to keyStrokes, do result[n-1] := 0 for breakpoint := n-3 down to 1, do curr := (n – breakpoint - 1)*result[breakpoint - 1] if curr > result[n-1], then result[n - 1] := curr done done result[keyStrokes - 1] End
示例
#include<iostream> using namespace std; int keyNumbers(int keystrokes) { //使用四种类型的按键查找"A"的数量 if (keystrokes <= 6) //如果按键次数少于 7 return keystrokes; int result[keystrokes]; //存储中间结果 for (int n=1; n<=6; n++) //最多 6 次按键,我们需要该数量的按键次数作为最大值 result[n-1] = n; for (int n=7; n<=keystrokes; n++) { //从第 7 个到更高版本 result[n-1] = 0; //初始存储 0 作为结果 for (int breakPoint=n-3; breakPoint>=1; breakPoint--) { //找到要选择的断点,复制并粘贴 int curr = (n-breakPoint-1)*result[breakPoint-1]; if (curr > result[n-1]) result[n-1] = curr; } } return result[keystrokes-1]; } int main() { int keystrokes; cout << "Enter Number of keystrokes: "; cin >> keystrokes; cout << "Maximum Number of A's with "<<keystrokes << " keystrokes is: "<< keyNumbers(keystrokes)<<endl; }
输出
Enter Number of keystrokes: 7 Maximum Number of A's with 7 keystrokes is: 9