如何使用提供的四个键来打印最多的 A
我们假设使用键盘写出字母“A”。我们的目标是只使用四个键,并尝试在文本字段上写出最多的“A”。这些键是“A”、“C”、“V”和“Ctrl”。
要写出最多的 A,我们将使用 Ctrl + A 来全选,使用 Ctrl + C 来复制,并使用 Ctrl + V 来粘贴。
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: 按键次数。
输出:使用这些按键次数得到的最多的字母数。
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
Enter Number of keystrokes: 7 Maximum Number of A's with 7 keystrokes is: 9
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