Fruit Feast（暴力）（动态规划)

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <climits>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <list>
#include<functional>
#define mod 1000000007
#define inf 0x3f3f3f3f
#define pi acos(-1.0)
using namespace std;
typedef long long ll;
const int N=5000005;
const int M=15005;
ll sum=1;
int n,m;
int vis[N];
int maxn=0;
struct man
{
  int num,use;
};
int main()
{
    int a,b;
    memset(vis,0,sizeof(vis));
    scanf("%d%d%d",&n,&a,&b);
    queue<man>q;
    man A;A.num=a;A.use=0;
    man B;B.num=b;B.use=0;
    q.push(A);q.push(B);
    vis[a]=1;vis[b]=1;
    while(!q.empty()){
        man t=q.front();
        q.pop();
        if(t.num+a>n)maxn=max(maxn,t.num);
        if(t.num+a<=n&&vis[t.num+a]==0){
            vis[t.num+a]=1;
            man k;k.num=t.num+a;k.use=t.use;
            q.push(k);
        }
        if(t.num+b>n)maxn=max(maxn,t.num);
        if(t.num+b<=n&&vis[t.num+b]==0){
            vis[t.num+b]=1;
                man k;k.num=t.num+b;k.use=t.use;
                q.push(k);
        }
        if(t.use==0&&vis[t.num/2]==0){
            vis[t.num/2]=1;
        man k;k.num=t.num/2;k.use=1;
            q.push(k);
        }
    }
    printf("%d\n",maxn);
    return 0;
}

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <climits>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <list>
#include<functional>
#define mod 1000000007
#define inf 0x3f3f3f3f
#define pi acos(-1.0)
using namespace std;
typedef long long ll;
const int N=5000005;
const int M=15005;
ll sum=1;
int n,m;
int vis[N];
int maxn=0;
int dp[N];
int main()
{
    int a,b;
    scanf("%d%d%d",&n,&a,&b);
    dp[0]=1;
    for(int i=a;i<=n;i++)dp[i]|=dp[i-a];
    for(int i=b;i<=n;i++)dp[i]|=dp[i-b];
    for(int i=0;i<=n;i++)dp[i/2]|=dp[i];
    for(int i=a;i<=n;i++)dp[i]|=dp[i-a];
    for(int i=b;i<=n;i++)dp[i]|=dp[i-b];
    for(a =n;dp[a]==0;a--);
    cout<<a<<endl;
    return 0;
}