归并排序

/**
 * 排序算法之归并排序
 */
#include <iostream>
#include <vector>
using namespace std;

void mergeKP(vector<int>& vec, int l1, int r1, int l2, int r2) {
    int i = l1;
    int j = l2;
    int n = (r1 - l1 + 1) + (r2 - l2 + 1);

    vector<int> temp(n);
    int k = 0;
    while (i <= r1 && j <= r2) {
        if (vec[i] < vec[j]) {
            temp[k++] = vec[i++];
        } else {
            temp[k++] = vec[j++];
        }
    }
    while (i <= r1) {
        temp[k++] = vec[i++];
    }
    while (j <= r2) {
        temp[k++] = vec[j++];
    }
    for (int i = 0; i < n; i++) {
        vec[l1 + i] = temp[i];
    }
}

void sortGuiBing(vector<int>& vec,int start, int end) {
    if (start < end) {
        int mid = (start + end) / 2;
        sortGuiBing(vec, start, mid);
        sortGuiBing(vec, mid + 1, end);
        mergeKP(vec, start, mid, mid + 1, end);
    }
}
int main() {
    vector<int> vec = {2,1,3,5,4};
    int len = vec.size();
    sortGuiBing(vec, 0, len - 1);
    for (int i = 0; i < len; ++i) {
        cout << vec[i] << endl;
    }
    return 0;
}