完全背包

#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
#pragma warning(disable:4996)
using std::cin;
using std::cout;
using std::endl;
using std::stringstream;
using std::string;
using std::vector;
using std::list;
using std::pair;
using std::set;
using std::multiset;
using std::map;
using std::multimap;
using std::stack;
using std::queue;
using std::priority_queue;
int main()
{
	//freopen("input.txt", "r", stdin);  
	//freopen("output.txt", "w", stdout);  
	int n, m;//商品的个数以及背包的容量
	while (cin >> n>>m)
	{
		//item.first表示该商品的价值，item.second表示该商品的重量
		vector<pair<int, int>>item(n);
		for (int i = 0; i < n; i++)
		{
			cin  >> item[i].first >> item[i].second;
		}
		//dp[i]表示重量恰好为i时的最大价值
		vector<int>dp(m + 1);
		for (int i = 0; i < n; i++)
		{
			dp[item[i].second] = std::max(dp[item[i].second],item[i].first);
			for (int j = 1; j <= m; j++)
			{
				if (dp[j] && j + item[i].second <= m)
				{
					dp[j + item[i].second] = std::max(dp[j + item[i].second], dp[j]+item[i].first);
				}
			}
		}
		int index = 0;
		for (int i = 0; i <= m; i++)
		{
			index = dp[index] > dp[i] ? index : i;
		}
		cout << dp[index] << endl;
	}
	return 0;
}