P1853 投资的最大效益

链接：https://www.luogu.com.cn/problem/P1853
题目：

总的思路就是完全背包模板加上空间优化
完全背包参考：https://blog.csdn.net/qq_40802813/article/details/119609917
空间优化见代码

#define _CRT_SECURE_NO_WARNINGS 
#include<iostream>
#include<vector>
#include<algorithm>
#include<math.h>
#include<sstream>
#include<string>
#include<string.h>
#include<iomanip>
#include<stdlib.h>
#include<map>
#include<queue>
#include<limits.h>
#include<climits>
#include<fstream>
#include<stack>
typedef long long ll;
using namespace std;
const int N = 1e7 + 1e5;
int n, C, dp[N];
int w[N], c[N];
int times;
int main()
{
	ios::sync_with_stdio(false); cin.tie(0), cout.tie(0);
	int d;
	cin >> C >> times >> d;
	for (int i = 1; i <= d; i++)
	{
		cin >> c[i] >> w[i];
	}
	for (int i = 0; i < times; i++)
	{
		int m = C / 1000;//这里！
		for(int i=1;i<=d;i++)
			for (int j = c[i]/1000; j <= m; j++)//以及j<=m
			{
				dp[j] = max(dp[j], dp[j - c[i]/1000] + w[i]);
			}
		C = dp[m] + C;
	}
	cout << C;

	return 0;
}