清北暑假模拟day1 生活

/*
数字三角形，要求第K大的值，可以推知，如果得知k的范围，那么一定是在上一行可转移状态的对应范围内（反证法可以证明），这个在背包九讲里也有提及
*/
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>

using namespace std;

int n,k,f[][][],z[][],y[];

int main()
{
    freopen("live.in","r",stdin);
    freopen("live.out","w",stdout);

    scanf("%d%d",&n,&k);
    for (int a=;a<=n;a++)
        for (int b=;b<=a;b++)
            scanf("%d",&z[a][b]);
    for (int a=;a<=n;a++)
        for (int b=;b<=a;b++)
            for (int c=;c<=k;c++)
                f[a][b][c]=-;
    f[][][]=z[][];
    for (int a=;a<n;a++)
        for (int b=;b<=a;b++)
            for (int c=;c<=k;c++)
                if (f[a][b][c]!=-)
                {
                    int v=f[a][b][c]+z[a+][b];
                    for (int d=;d<=k;d++)
                        if (v>=f[a+][b][d])
                        {
                            for (int e=k;e>d;e--)
                                f[a+][b][e]=f[a+][b][e-];
                            f[a+][b][d]=v;
                            break;
                        }
                    v=f[a][b][c]+z[a+][b+];
                    for (int d=;d<=k;d++)
                        if (v>=f[a+][b+][d])
                        {
                            for (int e=k;e>d;e--)
                                f[a+][b+][e]=f[a+][b+][e-];
                            f[a+][b+][d]=v;
                            break;
                        }
                }
    int cnt=;
    for (int a=;a<=n;a++)
        for (int b=;b<=k;b++)
            y[++cnt]=f[n][a][b];
    sort(y+,y+cnt+);
    printf("%d\n",y[cnt-k+]);

    return ;
}