一维数组A[m+n]，前m项和后n项分别为线性表（a1,a2,...,am）和（b1,b2,...,bn），现要求将其交换位置，变为（b1,b2,...,bn,a1,a2,...,am）。

本人代码片段如下：

void ExchangeAB(SeqList &L, int m, int n){
if (m < 1 || n < 1) {
    return;
}
int p = m, q = n, t; //p为每次交换的左边数列元素数，q为每次交换的右边数列元素数；
int left = 0, right = m + n - 1; //每次交换的左边界和右边界

while (q > 0 && p > 0 && left < right) { //当数列未交换完毕
    if (p > q) {          //若左边比右边长
        for (int i = left; i < left + q; i++) {
            t = L.data[i];
            L.data[i] = L.data[i + p];
            L.data[i + p] = t;
        }
        left += q;  //修改左边界
        p -= q;  //修改左边数列长度
    } else {     //若左边比右边短
        for (int i = left; i < left + p; i++) {
            t = L.data[i];
            L.data[i] = L.data[i + q];
            L.data[i + q] = t;
        }
        right -= p;  //修改右边界
        q -= p; //修改右边数列长度
    }
  }
}

该算法时间复杂度仅有O(n)，利用分治法思想完成，仅需遍历一遍数列即可。
完整可运行代码如下：

#include <iostream>
#define MaxSize 50
 using namespace std;

typedef struct  {
  int data[MaxSize];
  int length;
}SeqList;

void OutputList(SeqList &L){
  for (int i = 0; i < L.length; i++) {
      cout << L.data[i];
  }
}

void CreateList(SeqList &L){
    int l;
    cout << "Please enter the length:";
    cin >> l;
    L.length = l;
    for (int i = 0;i<L.length;i++) {
        cout << "Please enter the num" << i << ":";
        cin >> L.data[i];
    }
}

void ExchangeAB(SeqList &L, int m, int n){
    if (m < 1 || n < 1) {
        return;
    }
    int p = m, q = n, t, left = 0, right = m + n - 1;
    
    while (q > 0 && p > 0 && left < right) {
        if (p > q) {
            for (int i = left; i < left + q; i++) {
                t = L.data[i];
                L.data[i] = L.data[i + p];
                L.data[i + p] = t;
            }
            left += q;
            p -= q;
        } else {
            for (int i = left; i < left + p; i++) {
                t = L.data[i];
                L.data[i] = L.data[i + q];
                L.data[i + q] = t;
            }
            right -= p;
            q -= p;
        }
    }
}

int main(int argc, char *argv[]) {
    SeqList L;
    CreateList(L);
    ExchangeAB(L, 3, 9); //自已设定m与n的值
    OutputList(L);
}