参考:
http://cuijiahua.com/blog/2018/01/algorithm_7.html
算法思想
该算法采用经典的分治(divide-and-conquer)策略(分治法将问题分(divide)成一些小的问题然后递归求解,而治(conquer)的阶段则将分的阶段得到的各答案"修补"在一起,即分而治之
#include <iostream>
#include <vector>
using namespace std;
class Solution
{
public:
void mergeSort(vector<int> &array)
{
int len = array.size();
if (len <= 0)
return;
vector<int> temp(len);
divide(array, 0, len - 1, temp);
}
private:
void divide(vector<int> &array, int left, int right, vector<int> temp)
{
if (left < right)
{
int mid = (left + right) / 2;
divide(array, left, mid, temp);
divide(array, mid + 1, right, temp);
conquer(array, left, mid, right, temp);
}
}
void conquer(vector<int> &array, int left, int mid, int right, vector<int> &temp)
{
int i = left;
int j = mid + 1;
int k = 0;
while (i <= mid && j <= right) //小的进入temp
{
if (array[i] <= array[j])
temp[k++] = array[i++];
else
temp[k++] = array[j++];
}
while (i <= mid)
temp[k++] = array[i++]; //如果前半段有剩余
while (j <= right)
temp[k++] = array[j++]; //如果后半段有剩余
//array.assign(temp.begin(), temp.end());
k = 0;
while (left <= right)
array[left++] = temp[k++];
}
};
int main()
{
Solution s;
vector<int> array{2, 3, 9, 6, 4, 5, 8};
s.mergeSort(array);
for (auto i : array)
cout << i;
cout << endl;
system("pause");
return 0;
}