uva 103

#include <iostream>
#include <string>
#include <cstring>
#include <algorithm>
#include <cstdio>

using namespace std;

int a[30 + 5][30 +5];
struct node{
    int o;
    int po;
}dis[30 + 5];
bool vis[30 + 5][30 + 5];
int n,k;

bool isOk(int x[],int y[]){
    for(int i = 0; i < k; i++)
        if(x[i] >= y[i])
            return false;
    return true;

}

bool cmp(node a, node b){
    return a.o < b.o;
}
int dfs(int x){
    int ans;
    int Max = 0;
    for(int i = 0; i < n; i++){
        if(vis[x][i]){
            if(dis[i].o)
                ans = 1 + dis[i].o;
            else
                ans = 1 + dfs(i);
            if(ans > Max)
                Max = ans;
        }
    }
    return Max;
}

int main(){

    while(~scanf("%d%d",&n,&k)){
        memset(vis,0,sizeof vis);
        memset(dis,0,sizeof dis);
        for(int i = 0; i < n; i++)
            for(int j = 0; j < k; j++)
                scanf("%d",&a[i][j]);
        for(int i = 0; i < n; i++)
            sort(a[i],a[i]+k);
        for(int i = 0; i < n; i++)
            for(int j = i+1; j < n; j++)
                if(isOk(a[i],a[j]))
                    vis[i][j] = 1;
                else if(isOk(a[j],a[i]))
                    vis[j][i] = 1;
        int Max = 0;
        int pos = 0;
        for(int i = 0; i < n; i++){
            dis[i].o = dfs(i);
            dis[i].po = i;
            if(dis[i].o > Max){
                Max = dis[i].o;
                pos = i;
            }
        }
        printf("%d\n",Max+1);
        sort(dis,dis+n,cmp);
        printf("%d ",pos+1);
        int temp = Max-1;
        int femp = pos;
        for(int i = n-1; i >= 0 && Max >= -1; i--){
            if(vis[femp][dis[i].po] && dis[i].o == temp){
                printf("%d ",dis[i].po+1);
                temp--;
                femp = dis[i].po;
            }

        }
        printf("\n");
    }
    return 0;
}

卡时间注意记忆化搜索，输出也不能太恶心，还可以递归