数组移动问题

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#include<stdio.h>void shiftleft(int *pInOut, int n){int i;int tmp;tmp = *pInOut;for (i = 0; i < n - 1; ++i){*pInOut = *(pInOut + 1);pInOut++;}*pInOut = tmp;}void shiftright(int *pInOut, int n){int i;int tmp;pInOut += n - 1;tmp = *pInOut;for (i = n - 1 ; i > 0; --i){*pInOut = *(pInOut - 1);--pInOut;}*pInOut = tmp;}void shiftN(int *pInOut, int n, int shiftN){int i;if(shiftN > 0){for(i = 0; i < shiftN % n; ++i)shiftleft(pInOut, n);}else{shiftN = -shiftN;for(i = 0; i < shiftN % n; ++i)shiftright(pInOut, n);}}int main(){int array[4] = {1, 2, 3, 4};int array1[3] = {1, 2, 3};int i;shiftN(array, 4, 5);for(i = 0; i < 4; ++i)printf("%d ",array[i]);printf("\n"); shiftN(array1, 3, -1);for(i = 0; i < 3; ++i)printf("%d ",array1[i]);printf("\n");return 0;}

数组移动操作,写一个函数void  shitfN(int *pInOut, int n, int shiftN),将pInOut指向的数组移动shiftN位,如果shiftN为正数,就左移,如果为负数就右移,n为数组的长度。例如,array[]={1, 2, 3, 4}, shiftN = 1,移动后的结果为,array[] ={ 2, 3, 4, 1}  

如果array[]={1, 2, 3},shiftN = -1,移动后的结果为,array[]={3, 1, 2}


时间复杂度为o(ShiftN*n),换个方法思考:

循环左移ShiftN个,效果等价于,前ShiftN个元素逆置,后n-ShiftN个元素逆置,最后n个元素整体逆置。时间复杂度为o(n).


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