杭电 hdu 1051 Wooden Sticks

贪心问题，不过错了几次，我先将数据按重量进行排序，同时把重量相同的按长度进行排序。然后每处理一个木头，就向后搜索，查找所有可以符合题意的木头。并将已处理的木头进行标记，避免重复查找。

/* THE ROGRAM IS MADE BY PYY */ /*----------------------------------------------------------------------------// URL : http://acm.hdu.edu.cn/showproblem.php?pid=1051 Name : Wooden Sticks Date : Wednesday, April 20, 2010 Time Stage : Result: 3846516 2011-04-20 23:26:42 Accepted 1051 46MS 344K 2469 B C++ pyy Test Data: Sample Input 99 4 2 1 9 2 5 4 8 5 4 9 1 8 2 6 2 5 2 4 9 2 8 2 6 2 5 2 Sample Output 2 2 1 //----------------------------------------------------------------------------*/ #include <iostream> #include <stdio.h> #include <string.h> using namespace std; struct node { int len, wei; }; void swap( node & lhs, node & rhs ) { node tmp = lhs; lhs = rhs; rhs = tmp; } node wood[5005]; int n, times; int hash[5005]; void out() { int i, j; for( i = 0; i < n; i++ ) printf("(%d, %d) ", wood[i].len, wood[i].wei ); puts("/n"); } void psort() { int i, j, k; int pmin, ipmin; for( i = 0; i < n; i++ ) { ipmin = n - 1; for( j = i; j < n; j++ ) if( wood[j].wei < wood[ipmin].wei || ( wood[j].wei == wood[ipmin].wei && wood[j].len < wood[ipmin].len ) ) ipmin = j; swap( wood[i], wood[ipmin] ); } } void process() { memset( hash, 0, sizeof( hash ) ); int i, j, k; times = 0; for( i = 0; i < n; i++ ) { if( hash[i] ) continue; ++times; for( j = i + 1, k = i; j < n; j++ ) { if( !hash[j] && wood[k].len <= wood[j].len ) { k = j; hash[j] = 1; } } } } int main( void ) { int i, j, k; int tcase; while( cin >> tcase ) { while( tcase-- ) { cin >> n; for( i = 0; i < n; i++ ) cin >> wood[i].len >> wood[i].wei; psort(); process(); cout << times << endl; } } return 0; }