0/1背包

 1 program package;
 2 const 
 3   maxm=200;maxn=30;
 4 var 
 5   m,n,j,i:integer;
 6   c,w: array[1..maxn] of integer;
 7   f:array[0..maxn,0..maxm] of integer;
 8 function max(x,y:integer):integer;            //求x和y的最大值
 9 begin
10   if x>y then max:=x else max:=y;
11 end;
12 
13 BEGIN
14 assign(input,‘package.in‘); 
15 assign(output,‘package.out‘);
16 reset(input);
17 rewrite(output);
18   readln(m,n);                            //背包容量m和物品数量n
19   for i:= 1 to n do
20      readln(w[i],c[i]);                    //每个物品的重量和价值
21   for i:=1 to n do
22    for j:=1 to m do
23     begin                            // f(i，x)表示前i件物品，总重量不超过x的最优价值
24       if j>=w[i]  then f[i,j]:=max(f[i-1,j-w[i]]+c[i],f[i-1,j])
25                    else f[i,j]:=f[i-1,j];
26     end;
27   writeln(f[n,m]);                    //f(n,m)为最优解
28 close(input); 
29 close(output);
30 END.

 1 program star_package;
 2 var
 3     i,j,k,n,m:longint;
 4     f:array[0..100000]of longint;
 5     w,c:array[0..2000]of longint;
 6 begin
 7   assign(input,‘package.in‘);
 8   assign(output,‘package.out‘); 
 9   reset(input);
10   rewrite(output);
11   fillchar(f,sizeof(f),0);
12   readln(m,n);                                //背包容量m和物品数量n
13   for i:=1 to n do 
14      readln(w[i],c[i]);                        //每个物品的重量和价值
15   for i:=1 to n do
16     for j:=m downto w[i] do                    //这里不能写成for j:=w[i] to m
17       if f[j-w[i]]+c[i]>f[j] then f[j]:=f[j-w[i]]+c[i];    // f(j)表示重量不超过j公斤的最大价值
18   writeln(f[m]);
19   close(input);
20   close(ouptut);
21 end.