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UVA - 103 - Stacking Boxes (动态规划)

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UVA - 103

Time Limit: 3000MS   Memory Limit: Unknown   64bit IO Format: %lld & %llu

 Status

Description

技术分享

Background

Some concepts in Mathematics and Computer Science are simple in one or two dimensions but become more complex when extended to arbitrary dimensions. Consider solving differential equations in several dimensions and analyzing the topology of an n-dimensional hypercube. The former is much more complicated than its one dimensional relative while the latter bears a remarkable resemblance to its ``lower-class‘‘ cousin.

The Problem

Consider an n-dimensional ``box‘‘ given by its dimensions. In two dimensions the box (2,3) might represent a box with length 2 units and width 3 units. In three dimensions the box (4,8,9) can represent a box 技术分享(length, width, and height). In 6 dimensions it is, perhaps, unclear what the box (4,5,6,7,8,9) represents; but we can analyze properties of the box such as the sum of its dimensions.

In this problem you will analyze a property of a group of n-dimensional boxes. You are to determine the longest nesting string of boxes, that is a sequence of boxes 技术分享 such that each box 技术分享 nests in box 技术分享 ( 技术分享 .

A box D = ( 技术分享 ) nests in a box E = ( 技术分享 ) if there is some rearrangement of the 技术分享 such that when rearranged each dimension is less than the corresponding dimension in box E. This loosely corresponds to turning box D to see if it will fit in box E. However, since any rearrangement suffices, box D can be contorted, not just turned (see examples below).

For example, the box D = (2,6) nests in the box E = (7,3) since D can be rearranged as (6,2) so that each dimension is less than the corresponding dimension in E. The box D = (9,5,7,3) does NOT nest in the box E = (2,10,6,8) since no rearrangement of D results in a box that satisfies the nesting property, but F = (9,5,7,1) does nest in box E since F can be rearranged as (1,9,5,7) which nests in E.

Formally, we define nesting as follows: box D = ( 技术分享 ) nests in box E = ( 技术分享 ) if there is a permutation 技术分享 of 技术分享 such that ( 技术分享 ) ``fits‘‘ in ( 技术分享 ) i.e., if 技术分享 for all 技术分享 .

The Input

The input consists of a series of box sequences. Each box sequence begins with a line consisting of the the number of boxes k in the sequence followed by the dimensionality of the boxes, n (on the same line.)

This line is followed by k lines, one line per box with the n measurements of each box on one line separated by one or more spaces. The 技术分享 line in the sequence ( 技术分享 ) gives the measurements for the 技术分享 box.

There may be several box sequences in the input file. Your program should process all of them and determine, for each sequence, which of the k boxes determine the longest nesting string and the length of that nesting string (the number of boxes in the string).

In this problem the maximum dimensionality is 10 and the minimum dimensionality is 1. The maximum number of boxes in a sequence is 30.

The Output

For each box sequence in the input file, output the length of the longest nesting string on one line followed on the next line by a list of the boxes that comprise this string in order. The ``smallest‘‘ or ``innermost‘‘ box of the nesting string should be listed first, the next box (if there is one) should be listed second, etc.

The boxes should be numbered according to the order in which they appeared in the input file (first box is box 1, etc.).

If there is more than one longest nesting string then any one of them can be output.

Sample Input

5 2
3 7
8 10
5 2
9 11
21 18
8 6
5 2 20 1 30 10
23 15 7 9 11 3
40 50 34 24 14 4
9 10 11 12 13 14
31 4 18 8 27 17
44 32 13 19 41 19
1 2 3 4 5 6
80 37 47 18 21 9

Sample Output

5
3 1 2 4 5
4
7 2 5 6

Source

Root :: AOAPC I: Beginning Algorithm Contests (Rujia Liu) :: Volume 5. Dynamic Programming 
Root :: Competitive Programming: Increasing the Lower Bound of Programming Contests (Steven & Felix Halim) :: Chapter 4. Graph :: Special Graph - DAG :: Single-Source Shortest/Longest Paths in DAG
Root :: Competitive Programming 2: This increases the lower bound of Programming Contests. Again (Steven & Felix Halim) :: Graph :: Special Graph (Directed Acyclic Graph) :: Single-Source Shortest/Longest Paths on DAG
Root :: Competitive Programming 3: The New Lower Bound of Programming Contests (Steven & Felix Halim) :: Graph :: Special Graph (Directed Acyclic Graph) :: Single-Source Shortest/Longest Paths on DAG
Root :: Competitive Programming: Increasing the Lower Bound of Programming Contests (Steven & Felix Halim) :: Chapter 3. Problem Solving Paradigms :: Dynamic Programming :: Longest Increasing Subsequence (LIS) - Classical

 Status





思路:将a数组每一维排序,如果有一列严格小于另一列,则可以构成一条有向边,构图之后再去寻找最长路。。


AC代码:

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

int n, k;
int a[32][12];
int map[32][32];
int d[32];
int flag;

int fun(int x, int y) {
	for(int i = 0; i < k; i++) {
		if(a[x][i] >= a[y][i]) return 0;
	}
	return 1;
}

int dp(int i) {
	int & ans = d[i];
	if(ans != -1) return ans;
	ans = 1;
	for(int j = 0; j < n; j++) 
		if(map[i][j]) {
			ans = max(ans, dp(j) + 1);
		}
	return ans;
} 

void print(int i) {
	if(flag) printf(" %d", i + 1);
	else {
		printf("%d", i + 1);
		flag = 1;
	}
	for(int j = 0; j < n; j++) 
		if(map[i][j] && d[i] == d[j] + 1) {
			print(j);
			break;
		}
}

int main() {
	while(scanf("%d %d", &n, &k) != EOF) {
		for(int i = 0; i < n; i++) {
			for(int j = 0; j < k; j++) {
				scanf("%d", &a[i][j]);
			}
			sort(a[i], a[i] + k);
		}
		
		memset(map, 0, sizeof(map));
		for(int i = 0; i < n - 1; i++) {
			for(int j = i + 1; j < n; j++) {
				if(fun(i, j)) map[i][j] = 1;
				else if(fun(j, i)) map[j][i] = 1;
			}
		}
		
		/*for(int i = 0; i < n; i++) {
			for(int j = 0; j < n; j++) {
				printf("%d ", map[i][j]);
			}
			printf("\n");
		}*/
		
		memset(d, -1, sizeof(d));
		int ans = -1, pos;
		for(int i = 0; i < n; i++) {
			int tmp = dp(i);
			if(tmp > ans) {
				ans = tmp; pos = i;
			}
		}
		
		flag = 0;
		printf("%d\n", ans);
		print(pos);
		printf("\n");
	}
	return 0;
}















UVA - 103 - Stacking Boxes (动态规划)

原文:http://blog.csdn.net/u014355480/article/details/44788319

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