hdu 5616 Jam's balance

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传送门：
http://acm.hdu.edu.cn/showproblem.php?pid=5616
题意：
砝码能拼重量问题，背包，很水，一发就过了,这个是开二维数组的背包，一会按照标解写个一维数组的正反背包！

#include<bits/stdc++.h>using namespace std;int a[25],dp[25][2050];int t,n,m,k;void solve(){    dp[0][0]=1;    for(int i=1;i<=n;i++){        for(int j=0;j<=2000;j++){            if(j-a[i]>=0&&dp[i-1][j-a[i]]) dp[i][j]=1;            if(dp[i-1][j]) dp[i][j]=1;            if(j+a[i]<=2000&&dp[i-1][j+a[i]]) dp[i][j]=1;        }    }}int main(){    cin>>t;    while(t--){        scanf("%d",&n);int sum=0;memset(dp,0,sizeof(dp));        for(int i=1;i<=n;i++) {            scanf("%d",&a[i]); sum+=a[i];        }        scanf("%d",&m);solve();        while(m--){            scanf("%d",&k);            if(k<0||k>sum||dp[n][k]==0){                puts("NO");continue;            }            puts("YES");        }    }}

一维正反背包

#include <cstdio>#include <cmath>#include <iostream>#include <cstdlib>#include <algorithm>#include <vector>#include <map>#include <set>#include <cstring>#include <string>using namespace std;typedef long long ll;const int inf = 0x3f3f3f3f;const int maxn = 20 + 5;const int maxm = 2000 + 5;int dp[maxm];int A[maxn];int N, M;int main() {    cin.sync_with_stdio(false);    int T;    cin >> T;    while(T--) {        cin >> N;        for(int i = 0; i < N; i++) {            cin >> A[i];        }        //init        memset(dp, 0, sizeof(dp));        dp[0] = 1;        //positive        for(int i = 0; i < N; i++) {            for(int j = maxm - 1; j >= A[i]; j--) {                 dp[j] |= dp[j - A[i]];            }        }        //negtive        for(int i = 0; i < N; i++) {            for(int j = 0; j < maxm - A[i]; j++) {                dp[j] |= dp[j+A[i]];            }        }        cin >> M;        for(int i = 0; i < M; i++) {             int k;             cin >> k;             if(dp[k]) {                cout << "YES" << endl;             } else {                cout << "NO" << endl;             }        }    }    return 0;}

更有吊炸天的bitset写法orz！！！！

#include<bits/stdc++.h>using namespace std;int main(){    int T;    scanf("%d",&T);    const int middle=2005;    while(T--)    {        int n,m;        scanf("%d",&n);        bitset<4015> dp;        dp[middle]=1;        for(int i=1;i<=n;i++)        {            int x;            scanf("%d",&x);            dp=dp|(dp<<x)|(dp>>x);        }        scanf("%d",&m);        while(m--)        {            int x;            scanf("%d",&x);            if(dp[middle-x]||dp[middle+x])                puts("YES");            else                puts("NO");        }    }    return 0;}

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