HDU1614 | UVA 103 Stacking Boxes

數塔類型的dp,記憶化搜索就可以了.

注意杭電的輸出最後有一個空格.

#include 
#include 
#include 
#include 
using namespace std;
const int MAX = 31;
struct Box{
	int dims[11];
}boxes[MAX];
bool g[MAX][MAX];
int dp[MAX], fa[MAX], n, k;
//check if box a can be nested into box b
bool can_be_nested(Box & a, Box & b, int len){
	for(int i = 0; i < len; ++i){
		if(a.dims[i] >= b.dims[i])return false;
	}
	return true;
}

int memoized_dfs(int i){
	if(dp[i] != 0)return dp[i];
	int max_len = 0;
	for(int j = 1; j <= k; ++j){
		if(g[i][j]){
			int next_len = memoized_dfs(j);
			if(next_len > max_len){
				max_len = next_len;
				fa[i] = j;
			}
		}
	}
	return dp[i] = max_len + 1;
}

int main(int argc, char const *argv[]){
	while(scanf("%d %d", &k, &n) == 2){
		memset(g, false, sizeof(g));
		for(int i = 1; i <= k; ++i){
			for(int j = 0; j < n; ++j){
				scanf("%d", &boxes[i].dims[j]);
			}
			sort(boxes[i].dims, boxes[i].dims + n);
		}
		for(int i = 1; i <= k; ++i){
			for(int j = 1; j <= k; ++j){
				if(can_be_nested(boxes[j], boxes[i], n)){
					g[i][j] = true;
				}
			}
		}
		vector ans;
		for(int i = 1; i <= k; ++i){
			memset(dp, 0, sizeof(dp));
			memset(fa, 0, sizeof(fa));
			
			int length = memoized_dfs(i);

			if(length > ans.size()){
				ans.clear();
				int p = i;

				while(p != 0){
					ans.push_back(p);
					p = fa[p];
				}
			}
		}
		printf("%d\n", ans.size());
		for(int i = ans.size() - 1; i >= 0; --i){
			if(i < ans.size() - 1)printf(" ");
			printf("%d", ans[i]);
		}
		printf("\n");
	}
	return 0;
}