排序算法之选择排序

题目传送门

/*
    用zstu3539题目来验证算法的正确性
*/
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <ctime>
#include <cstdlib>
using namespace std;

const int maxn = 1000000 + 10;
const int INF = 0x3f3f3f3f;
int a[maxn];

void SelectSort(int *a, int n)
{
    for (int i=1; i<=n; ++i)
    {
        int mn = a[i];    int k = i;
        for (int j=i+1; j<=n; ++j)
        {
            if (mn > a[j])
            {
                mn = a[j];
                k = j;
            }
        }
        if (mn != a[i])
            swap (a[i], a[k]);
    }
}

void SelectSort_2(int *a, int n)        //每次分配最大值和最小值，还有bug
{
    for (int i=1; i<=n/2+1; ++i)
    {
        int mn_id = i, mx_id = n - i + 1;
        for (int j=i+1; j<=n-i; ++j)
        {
            if (a[j] > a[mx_id])
            {
                mx_id = j;    continue;
            }
            if (a[j] < a[mn_id])    mn_id = j;
        }
        swap (a[i], a[mn_id]);
        swap (a[n-i+1], a[mx_id]);
    }
}

int main(void)
{
    //freopen ("rand_small.in", "r", stdin);
    int n;

    while (scanf ("%d", &n) != EOF)
    {
        if (n == 0)
            continue;
        for (int i=1; i<=n; ++i)
        {
            scanf ("%d", &a[i]);
        }
    
        SelectSort (a, n);
        //SelectSort_2 (a, n);

        bool flag = true;
        for (int i=1; i<=n; ++i)
        {
            if (flag)
            {
                printf ("%d", a[i]);
                flag = false;
            }
            else
                printf (" %d", a[i]);
        }
        puts ("");
    }

    return 0;
}