HDU 1074 doing homework

Http://acm.hdu.edu.cn/showproblem.php? PID = 1, 1074

Pressure DP is not very familiar, look at other people's code to write, a long time to understand. DP [I] records (1 <n)-the minimum result of the I state in 1 state. Use the pre array to record the precursor of each status.

Use the DFS output path.

 1 #include <cstdio> 2 #include <cstring> 3 #include <algorithm> 4 #define maxn 16 5 using namespace std; 6 const int inf=1<<29; 7  8 int dp[1<<16]; 9 int t,n;10 int pre[1<<16];11 struct node12 {13     char name[110];14     int d;15     int c;16 }p[maxn*10];17 18 void dfs(int w)19 {20     if(w==0) return ;21     int pos=0;22     for(int i=0; i<n; i++)23     {24         if((w&(1<<i))!=0&&(pre[w]&(1<<i))==0)25         {26             pos=i;27             break;28         }29     }30     dfs(pre[w]);31     printf("%s\n",p[pos].name);32 }33 34 int main()35 {36     scanf("%d",&t);37     while(t--)38     {39         scanf("%d",&n);40         for(int i=0; i<n; i++)41         {42             scanf("%s%d%d",p[i].name,&p[i].d,&p[i].c);43         }44         for(int i=0; i<(1<<n); i++)45         {46             dp[i]=inf;47         }48         dp[0]=0;49         for(int i=0; i<(1<<n); i++)50         {51             for(int j=0; j<n; j++)52             {53                 if(i&(1<<j)) continue;54                 int sum=0;55                 for(int k=0; k<n; k++)56                 {57                     if(i&(1<<k)) sum+=p[k].c;58                 }59                 sum+=p[j].c;60                 if(sum>p[j].d) sum-=p[j].d;61                 else sum=0;62                 if(dp[i|(1<<j)]>dp[i]+sum)63                 {64                     dp[i|(1<<j)]=dp[i]+sum;65                     pre[i|(1<<j)]=i;66                 }67             }68         }69         printf("%d\n",dp[(1<<n)-1]);70         dfs((1<<n)-1);71     }72     return 0;73 }

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HDU 1074 doing homework