C++归并排序

C++归并排序

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void merge(vector<int> &data, int start, int mid, int end) {
    vector<int> tmp;
    int i = start, j = mid + 1;
    while (i < mid + 1 && j < end + 1)
    {
        if (data[i] <= data[j])
            tmp.push_back(data[i++]);
        else
            tmp.push_back(data[j++]);
    }
    while (i < mid + 1)
        tmp.push_back(data[i++]);
    while (j < end + 1)
        tmp.push_back(data[j++]);
    for (int m = 0; m < tmp.size(); m++)
        data[start+m] = tmp[m];  // 注意
}

void merge_sort(vector<int> &data, int start, int end)
{
    if (start < end)
    {
        int mid = (start + end) / 2;
        merge_sort(data, start, mid);
        merge_sort(data, mid+1, end);
        merge(data, start, mid, end);
    }
}

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