# 背包问题

#include<stdio.h>
#define N 7
#define S 15
int w[N+1]={0,1,4,3,4,5,2,7};
int knap(int s,int n)
{
if(s==0) return 1;
if(s<0||(s>0 && n<1)) return 0;
if(knap(s-w[n],n-1)){
printf("%4d",w[n]);
return 1;
}
return knap(s,n-1);
}
main()
{
if(knap(S,N)) printf("\nOK!\n");
else printf("NO!\n");
}

#include <stdio.h>
#define N 7
#define S 15
typedef struct{
int s;
int n;
int job;
}KNAPTP;
int w[N+1]={0,1,4,3,4,5,2,7};
int knap(int s,int n);
main()
{
if(knap(S,N)) printf("OK!\n");
else printf("NO!\n");
}
int knap(int s,int n)
{
KNAPTP stack[100],x;
int top,k,rep;
x.s=s; x.n=n;
x.job=0;
top=1; stack[top]=x;
k=0;
while(top>=1&&!k){
x=stack[top];
rep=1;
while(!k && rep){
if(x.s==0) k=1;
else if(x.s<0 || x.n<=0) rep=0;
else{
x.s=x.s-w[x.n--];
x.job=1;
stack[++top]=x;
}
}
if(!k){
rep=1;
while(top>=1 && rep){
x=stack[top--];
if(x.job==1){
x.s+=w[x.n+1];
x.job=2;
stack[++top]=x;
rep=0;
}
}
}
}
if(k){
while(top >=1){
x=stack[top--];
if(x.job==1) printf("%4d\t",w[x.n+1]);
}
}
return k;
}

posted @ 2011-11-09 23:51 残星 阅读(...) 评论(...) 编辑 收藏