uva103-Stacking_Boxes

题目链接请戳 这里

解题思路

DAG上的动态规划。现对n个维度排序（感觉有维度的，先排序排序就行了

代码

#include<stdio.h>
#include<string.h>
#include<algorithm>
#define N 40
using namespace std;

bool G[N][N];
int box[N][N], dp[N];
int k, n;
bool first;

bool judge(int x, int y)
{
    bool flag = true;
    for (int i = 0; i < n; i++) if (box[x][i] >= box[y][i]) flag = false;
    return flag;
}

int cal(int i)
{
    int &ans = dp[i];
    if (ans > 0) return ans;
    ans = 1;
    for (int j = 1; j <= k; j++) if (G[i][j])
        ans = max(ans, cal(j) + 1);
    return ans;
}

void print_ans(int i)
{
    if (first) { printf("%d", i); first = false; }
    else printf("% d", i);
    for (int j = 1; j <= k; j++) if (G[i][j] && dp[i] == dp[j] + 1) {
        print_ans(j);
        break;
    }
}

int main()
{
    while (scanf("%d%d", &k, &n) != EOF) {
        memset(G, false, sizeof(G));
        for (int i = 1; i <= k; i++)
            for (int j = 0; j < n; j++)
                scanf("%d", &box[i][j]);
        for (int i = 1; i <= k; i++) sort(box[i], box[i] + n);
        for (int i = 1; i <= k; i++)
            for (int j = 1; j <= k; j++) if (judge(i, j))
                G[i][j] = true;
        memset(dp, 0, sizeof(dp));
        for (int i = 1; i <= k; i++) cal(i);
        int max_index = 1;
        for (int i = 1; i <= k; i++) if (dp[i] > dp[max_index]) max_index = i;
        first = true;
        printf("%d\n", dp[max_index]);
        print_ans(max_index);
        printf("\n");
    }
    return 0;
}