C :

#include <stdio.h>   
  
int main()  
{  
    int  dp[30000];
    int n,m;
    int i,j; 
    while(scanf("%d%d",&n,&m)!=EOF)    
    {  
        for(j=1;j<=m;j++)  
        {  
            int v,p;     
            scanf("%d%d",&v,&p); 
            for(int i=n;i>=v;i--)  
                if(dp[i]<dp[i-v]+v*p)  
                    dp[i]=dp[i-v]+v*p;  
        }  
        int max=0;  
        for(i=1;i<n;i++)  
            if(dp[i]>max)  
                max=dp[i];  
        printf("%d\n",max);  
        //memset(dp,0,sizeof(dp));  
    }  
    return 0;  
}  

C++ :

#include <iostream>
//状态转移方程:
//F[i] = max{F[v],F[v-Ci]+Wi*Ci}
using namespace std;
int C[30];
int W[30];
int F[30000] = {0};
int main()
{
	int N,m;
	cin >> N >> m;
	for(int i=1; i<=m; ++i)
		cin >> C[i] >> W[i];
	for(int i=1; i<=m; ++i)
		for(int v=N; v>=C[i]; --v)
		{
			if(F[v-C[i]]+W[i]*C[i] > F[v])
				F[v] = F[v-C[i]]+W[i]*C[i];	
		}
	cout << F[N]<< endl;
	return 0;
}

Pascal :

var n,m,i,max:longint;a,b:array[0..25]of longint;
procedure try(t,s,x:longint);
var i:longint;
begin
 if t>m then
  begin
   if (s<=n)and(x>max)then max:=x;
   exit;
  end;
 for i:=0 to 1 do
  if i=1 then try(t+1,s+a[t],x+b[t]*a[t])
  else try(t+1,s,x);
end;
begin
 read(n,m);
 for i:=1 to m do read(a[i],b[i]);
 max:=-1;
 try(1,0,0);
 writeln(max);
end.