HDU Wooden Sticks (贪心)

Wooden Sticks Time Limit : 2000/1000ms (Java/Other)Memory Limit : 65536/32768K (Java/Other)Total Submission(s) : 19Accepted Submission(s) : 7Font: Times New Roman | Verdana | Georgia Font Size: ← →Problem Description

There is a pile of n wooden sticks. The length and weight of each stick are known in advance. The sticks are to be processed by a woodworking machine in one by one fashion. It needs some time, called setup time, for the machine to prepare processing a stick. The setup times are associated with cleaning operations and changing tools and shapes in the machine. The setup times of the woodworking machine are given as follows:(a) The setup time for the first wooden stick is 1 minute. (b) Right after processing a stick of length l and weight w , the machine will need no setup time for a stick of length l’ and weight w’ if l<=l’ and w<=w’. Otherwise, it will need 1 minute for setup.You are to find the minimum setup time to process a given pile of n wooden sticks. For example, if you have five sticks whose pairs of length and weight are (4,9), (5,2), (2,1), (3,5), and (1,4), then the minimum setup time should be 2 minutes since there is a sequence of pairs (1,4), (3,5), (4,9), (2,1), (5,2).

Input

The input consists of T test cases. The number of test cases (T) is given in the first line of the input file. Each test case consists of two lines: The first line has an integer n , 1<=n<=5000, that represents the number of wooden sticks in the test case, and the second line contains n 2 positive integers l1, w1, l2, w2, …, ln, wn, each of magnitude at most 10000 , where li and wi are the length and weight of the i th wooden stick, respectively. The 2n integers are delimited by one or more spaces.

Output

The output should contain the minimum setup time in minutes, one per line.

Sample Input

3 5 4 9 5 2 2 1 3 5 1 4 3 2 2 1 1 2 2 3 1 3 2 2 3 1

Sample Output

213

Source

Asia 2001, Taejon (South Korea)

AC代码:

#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>using namespace std;struct wooden{int l,w;};wooden my[5010];bool comp(wooden a,wooden b){if(a.l>b.l)return 1;else if(a.l==b.l)return a.w>b.w;else return 0;}int main(){int t;cin>>t;while(t–){int n;cin>>n;int i=0,j;while(i<n)cin>>my[i++].l>>my[i].w;sort(my,my+n,comp);//for(i=0;i<n;++i)cout<<my[i].l<<' '<<my[i].w<<'\12';int out=n;for(i=1;i<n;i++)for(j=0;j<=i-1;j++){if(my[j].l>=my[i].l&&my[j].w>=my[i].w){out–;my[j].l=my[i].l;my[j].w=my[i].w;my[i].l=0;my[i].w=0;break;}}// for(i=0;i<n;++i)cout<<my[i].l<<' '<<my[i].w<<'\12';cout<<out<<'\12';}return 0;}

,人生才会更有意义。如果没有梦想,那就托做庸人。

HDU Wooden Sticks (贪心)

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