学步园

编程珠玑I第2版 P14

数组循环移位即求:

AB=>BA

A、B为2个向量

而BA=（ArBr）r，r为对向量颠倒

#include <iostream><br /> #include <vector><br /> #include <cassert><br /> #include <algorithm><br /> using namespace std;</p> <p>void Reverse(int A[],int l,int r)<br /> {<br /> for(;l<r;l++,r--)<br /> {<br /> int temp=A[l];<br /> A[l]=A[r];<br /> A[r]=temp;<br /> }<br /> }</p> <p>//if c is positive:leftShift else rightshift<br /> void Shift(int A[],int l,int r,int c)<br /> {<br /> int len=r-l+1;<br /> assert(len>=1);<br /> c%=len;<br /> if(c<0)<br /> c+=len;<br /> Reverse(A,l,l+c-1);<br /> Reverse(A,l+c,r);<br /> Reverse(A,l,r);<br /> }</p> <p>void PrintArray(int A[],unsigned len)<br /> {<br /> for(int i=0;i<len;i++)<br /> cout << A[i] << '/t';<br /> }</p> <p>int main()<br /> {<br /> int A[]={1,2,3,4,5,6,7};<br /> int len=sizeof(A)/sizeof(int);<br /> PrintArray(A,len);<br /> cout << endl;<br /> for(int i=-10;i<10;i++)<br /> {<br /> cout << i << ':' << endl;<br /> Shift(A,0,len-1,i);<br /> PrintArray(A,len);<br /> cout << endl;<br /> Shift(A,0,len-1,-i);<br /> PrintArray(A,len);<br /> cout << endl;<br /> }<br /> system("pause");<br /> return 0;<br /> }

按单词反转字符串，即:

输入:Rose is red.

输出:red. is Rose

即:

AB...XYZ=>ZYX...BA

A,B....均为一个向量(字符串中即为单词、空格符)

ZYX...BA=(ArBr...XrYrZr)r，r为向量颠倒

#include <iostream><br /> #include <string><br /> #include <cassert><br /> #include <set><br /> #include <algorithm><br /> #include <windows.h><br /> #include <stack><br /> #include <vector><br /> #include <time.h><br /> #include <windows.h><br /> #include <fstream><br /> using namespace std;</p> <p>char sentence[1000];</p> <p>void Reverse(char arr[],int left,int right)<br /> {<br /> for(int i=left,j=right;i<j;i++,j--)<br /> swap(arr[i],arr[j]);<br /> }</p> <p>void ReverseWordInSentence(char sen[])<br /> {<br /> int len=strlen(sen);<br /> int i=0,j=-1;<br /> while(1)<br /> {<br /> while(i < len && isspace(sen[i]))<br /> i++;<br /> if(i >= len)<br /> break;<br /> j=i;<br /> while(j < len && !isspace(sen[j]))<br /> j++;<br /> j-=1;<br /> //maintain [i,j] is a word<br /> Reverse(sen,i,j);<br /> i=j+1;<br /> }<br /> Reverse(sen,0,len-1);<br /> }</p> <p>int main ()<br /> {<br /> while(1)<br /> {<br /> gets(sentence);<br /> ReverseWordInSentence(sentence);<br /> printf("%s/n/n",sentence);<br /> }<br /> system("pause");<br /> return 0;<br /> }<br />

由于空格符如space,/t等是否颠倒对显示出来的效果无影响，所以不错颠倒的处理