如何使用给定的四个键打印A的最大数量
让我们考虑一下，我们将尝试使用键盘写字母“A”。我们的目标是仅使用四个键，并尝试在文本字段上写入最大的'A'。键是“A”，“C”，“V”和“Ctrl”。
要写入最大数量的A，我们将使用Ctrl+A选择全部，使用Ctrl+C复制并使用Ctrl+V粘贴。
输入输出
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：使用这些按键的最大字母数。
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) { //find number of 'A's using 4 types of keys
if (keystrokes <= 6) //if keystrokes are less than 7
return keystrokes;
int result[keystrokes]; //store intermediate results
for (int n=1; n<=6; n++) //upto 6 keystrokes, we need that number of keystrokes for max
result[n-1] = n;
for (int n=7; n<=keystrokes; n++) { //for 7th to higher
result[n-1] = 0; //initially store 0 as result
for (int breakPoint=n-3; breakPoint>=1; breakPoint--) { //find breakpoint to select, copy and paste
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;
}输出结果
Enter Number of keystrokes: 7 Maximum Number of A's with 7 keystrokes is: 9