HDU5890_Eighty seven_排除物品的01背包&&bitset

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题意

给出 n 个数，进行 m 轮判断。每一轮去掉最多三个数，问从剩下的数中选恰好10个数的和恰好是87。

思路

bitset暴力01背包。

题目链接

http://acm.hdu.edu.cn/showproblem.php?pid=5890

AC代码

#include<cstdio>#include<iostream>#include<bitset>#include<algorithm>#include<cstring>using namespace std;const int maxn = 60;int T, n, m;int A[maxn];int ans[maxn][maxn][maxn];bitset<90> dp[11];bool Judge(int a, int b, int c){    for(int i = 0; i <= n; i++) dp[i].reset();    dp[0][0] = 1;    for(int i = 1; i <= n; i++)    {        if(i == a || i == b || i == c) continue;        for(int j = 10; j >= 1; j--)            dp[j] |= dp[j-1] << A[i];    }    return dp[10][87];}int main(){    scanf("%d", &T);    while(T--)    {        memset(ans, 0, sizeof ans);        scanf("%d", &n);        for(int i = 1; i <= n; i++)            scanf("%d", &A[i]);        for(int i = 1; i <= n; i++)        {            for(int j = i; j <= n; j++)            {                for(int k = j; k <= n; k++)                    if(Judge(i, j, k)){                        ans[i][j][k]=ans[i][k][j]=1;                        ans[j][i][k]=ans[j][k][i]=1;                        ans[k][i][j]=ans[k][j][i]=1;                    }            }        }        scanf("%d", &m);        while(m--)        {            int a, b, c;            scanf("%d %d %d", &a, &b, &c);            if(ans[a][b][c]) puts("Yes");            else puts("No");        }    }    return 0;}

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