C :

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int cmp ( const void *a , const void *b )
{
	return *(int *)a - *(int *)b;
}
int get_min(int num[], int cnt)
{
	qsort(num, cnt, sizeof(int), cmp);
	return num[0];
}
int main()
{
	int m, n;
	while (scanf("%d%d", &m, &n) == 2)
	{
		int *wi = (int*)malloc(sizeof(int) * (m + 1));
		int i, sum = 0;
		for (i = 0; i < m; i++)
		{
			scanf("%d", &wi[i]);
			sum += wi[i];
		}
		int time = 0, sum_ = 0;
		while (sum != sum_)
		{
			int cnt = 0;
			int *temp = (int*)malloc(sizeof(int) * n);
			memset(temp, 0, sizeof(int)*n);
			for (i = 0; i < m; i++)
			{
				if (wi[i] != 0)
				{
					temp[cnt] = wi[i];
					cnt++;
				}
				if (cnt == n || i == m - 1) break;
			}
			int min = get_min(temp, cnt);
			time += min, sum_ += cnt * min;
			for (i = 0, cnt = 0; i < m; i++)
			{
				if (wi[i] != 0)
				{
					wi[i] -= min;
					cnt++;
				}
				if (cnt == n || i == m - 1) break;
			}
			free(temp);
		}
		printf("%d\n", time);
		free(wi);
	}
	return 0;
}

C++ :

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<string>
#include<cmath>
#include<vector>
#include<queue>
using namespace std;
int a[10010];
int main()
{
    int i,j,k,t,m,n,mm;

    while(cin>>m>>n)
    {
        for(i=0;i<m;i++)
            cin>>a[i];
           int  kk=m;
           int ans=0;i=0;
           if(kk>n)
           {
            while(kk>n)
            {
              sort(a+i,a+n+i);
                 ans=ans+a[i];
                   int num=a[i];
                for(j=i; j<n+i; j++)
                {
                     a[j]=a[j]-num;
                      if(a[j]==0)
                      {mm=j;kk--;}
                }
//                for(int kkk=0;kkk<m;kkk++)
//                    cout<<a[kkk]<<" ";
//                    cout<<endl;
                  i=mm+1;
               }
           }
               sort(a,a+m);
          // cout<<a[m-1]<<endl;
            ans=ans+a[m-1];
            cout<<ans<<endl;
    }
    return 0;
}