八种常见的排序算法

算法性质

算法 稳定性 时间复杂度 计数排序 稳定 O(n) 基数排序 稳定 O(n) 桶排序 不稳定 O(n) 插入排序 稳定 O(n^2) 归并排序 稳定 O(nlogn) 快速排序 不稳定 O(nlogn) 希尔排序 不稳定 O(n^2) 堆排序 不稳定 O(nlogn)

代码实现

#include<iostream>#include<vector>using namespace std;namespace sort{/** * 计数排序 **/void count_sort(vector<int>& in) {    int max_val = 0;    for (auto ele : in) {        if (ele < 0) return;        max_val = max(max_val, ele);    }    vector<int> counter(max_val, 0);    for (auto ele : in) counter[ele] += 1;    int cur = 0;    for (int i = 0; i < counter.size(); ++i) {        if (counter[i] != 0) {            int tmp = cur;            cur += counter[i];            while(tmp < cur) in[tmp++] = i;        }    }}/** * 基数排序 **/int get_digit(int n, int pos) {    while (pos > 0) {        n /= 10;        pos--;    }    return n % 10;}int get_digit_length(int n) {    int len = 0;    while (n > 0) {        n /= 10;        len++;    }    return len;}void radix_sort(vector<int>& in) {    int max_len = 0;    for (auto ele : in) max_len = max(max_len, get_digit_length(ele));    for (int k = 0; k < max_len; ++k) {        int count[10] = {0};        for (auto ele : in) {            int radix = get_digit(ele, k);            count[radix]++;        }        int pos[10] = {0};        for (int i = 1; i < 10; ++i) pos[i] = pos[i - 1] + count[i - 1];        vector<int> in_tmp(in.begin(), in.end());        for (auto ele : in_tmp) {            int radix = get_digit(ele, k);            in[pos[radix]++] = ele;        }        cout<<">>Loop:"<<k<<"<<"<<endl;        for (auto ele : in) cout<<ele<<",";        cout<<endl;    }}/** * 桶排序 **/void insert(vector<int>& in, int ele) {    in.push_back(0);    int i = in.size() - 2;    while (i >= 0 && in[i] > ele) {        in[i + 1] = in[i];        i--;    }    in[i + 1] = ele;}int get_bucket_index(int ele, int min_val, int max_val, int bucket_num) {    int bucket_range = (max_val + 1 - min_val) / bucket_num;    int ret = (ele - min_val) / bucket_range;    return ret;}void bucket_sort(vector<int>& in, int bucket_num = 10) {    vector<vector<int> > bucket(bucket_num + 1, vector<int>());    int max_val = numeric_limits<int>::min();    int min_val = numeric_limits<int>::min();    for (auto ele : in) {        min_val = min(ele, min_val);        max_val = max(ele, max_val);    }    for (auto ele : in) {        int key = get_bucket_index(ele, min_val, max_val, bucket_num);        insert(bucket[key], ele);    }    int j = 0;    for (int i = 0; i < bucket_num + 1; ++i) {        for (auto ele : bucket[i]) in[j++] = ele;     }}/** * 归并排序 **/vector<int> merge_sort(vector<int>& in, int beg, int end) {    vector<int> ret;    if (beg >= end) return ret;    if (beg == end - 1) {        ret.push_back(in[beg]);        return ret;    }    int mid = (end + beg) / 2;    auto left = merge_sort(in, beg, mid);    auto right = merge_sort(in, mid, end);    int i = 0, j = 0;    while (i < left.size() && j < right.size()) {        if (left[i] <= right[j]) {            ret.push_back(left[i++]);        } else {            ret.push_back(right[j++]);        }    }    while (i < left.size()) {        ret.push_back(left[i++]);    }    while (j < right.size()) {        ret.push_back(right[j++]);    }    return ret;}void merge_sort(vector<int>& in) {    auto ret = merge_sort(in, 0, in.size());    int i = 0;    for (auto ele : ret) {        in[i++] = ele;    }}/** * 快速排序 **/int devide(vector<int>& in, int beg, int end) {    int pivot = in[beg];    int e = end - 1, b = beg;    while (b < e) {        while (e > b && in[e] >= pivot) e--;        in[b] = in[e];        while (b < e && in[b] < pivot) b++;        in[e] = in[b];    }    in[b] = pivot;    return b;}void quick_sort_seg(vector<int>& in, int beg, int end) {    if (beg < end) {        int mid = devide(in, beg, end);        quick_sort_seg(in, beg, mid);        quick_sort_seg(in, mid + 1, end);    }}void quick_sort(vector<int>& in) {   quick_sort_seg(in, 0, (int)in.size()); }/** * 直接插入排序 **/void insert_sort(vector<int>& in) {    for (int i = 1; i < in.size(); ++i) {        int tmp = in[i];        int j = i - 1;        while (j >= 0 && in[j] > tmp) {            in[j + 1] = in[j];            j--;        }        in[j + 1] = tmp;    }}/** * 希尔排序 **/void shell_sort(vector<int>& in) {    vector<int> steps = {16, 8, 4, 2, 1};    for (auto step : steps) {        for (int i = step; i < in.size(); i += step) {            int tmp = in[i];            int j = i - step;            while (j >= 0 && in[j] > tmp) {                in[j + step] = in[j];                j -= step;            }            in[j + step] = tmp;        }    }}/** * 堆排序 **/int l_child(int parent) {    return ((parent + 1)<<1) - 1;}int r_child(int parent) {    return (parent + 1)<<1;}void heapify(vector<int>& in, int top, int end) {    if (top >= end) return;    int lc_index = l_child(top);    int rc_index = r_child(top);    if (lc_index >= end) lc_index = top;    if (rc_index >= end) rc_index = top;    int max_index = top;    if (in[lc_index] > in[max_index]) max_index = lc_index;    if (in[rc_index] > in[max_index]) max_index = rc_index;    if (max_index == top) return;    swap(in[max_index], in[top]);    heapify(in, max_index, end);}void heap_sort(vector<int>& in) {    for (int i = in.size() / 2; i >= 0; --i) heapify(in, i, in.size());    int len = in.size();    while (len > 0) {        swap(in[0], in[len - 1]);        len -= 1;        heapify(in, 0, len);    }}};int main() {    int n = 0;    cin>>n;    vector<int> data;    for (int i = 1; i <= n; ++i) {        int tmp;        cin>>tmp;        data.push_back(tmp);    }    //sort::count_sort(data);    //sort::radix_sort(data);    //sort::bucket_sort(data);    //sort::merge_sort(data);    //sort::quick_sort(data);    //sort::insert_sort(data);    //sort::shell_sort(data);    sort::heap_sort(data);    for (auto ele : data) cout<<"\t"<<ele;    cout<<endl;    return 0;}