POJ 1051 Jury Compromise ——（暴力DP）

　　题目不难，暴力地dp一下就好，但是不知道我WA在哪里了，对拍了好多的数据都没找出错误= =。估计又是哪里小细节写错了QAQ。。思路是用dp[i][j]表示已经选了i个，差值为j的最大和。转移的话暴力枚举当前选那个即可。代码如下（WA的，以后有机会再找找错在哪里吧0.0）：

 #include <stdio.h>
 #include <algorithm>
 #include <string.h>
 #include <set>
 using namespace std;
 const int N =  + ;

 int n,m;
 int a[N],b[N];
 struct node
 {
     int now,pre,val;
     int a,b;
 }dp[+][+];

 set<int> get(int x)
 {
     set<int> S;
     for(int i=m;i>=;i--)
     {
         S.insert(dp[i][x].now);
         x = dp[i][x].pre;
     }
     return S;
 }

 int main()
 {
     int kase = ;
     while(scanf("%d%d",&n,&m) == )
     {
         if(n ==  & m == ) break;
         for(int i=;i<=n;i++) scanf("%d%d",a+i,b+i);
         for(int i=;i<=;i++) dp[][i] = (node){-,-,,,};
         dp[][] = (node){,-,,,};
         for(int i=;i<=m;i++)
         {
             for(int j=;j<=;j++)
             {
                 dp[i][j] = (node){-,-,,,};
                 for(int k=;k<=n;k++)
                 {
                     int add = a[k] - b[k];
                     if(j-add <  || j - add > ) continue;
                     int pre = j - add;
                     if(dp[i-][pre].now == -) continue;
                     int flag = ;
                     for(int p=i-;p>=;p--)
                     {
                         if(dp[p][pre].now == k)
                         {
                             flag = ;
                             break;
                         }
                         else pre = dp[p][pre].pre;
                     }
                     if(flag == ) continue;
                     if(dp[i-][j - add].val + a[k]+b[k] > dp[i][j].val)
                     {
                         dp[i][j] = (node){k,j-add,dp[i-][j - add].val + a[k]+b[k],
                         dp[i-][j - add].a + a[k], dp[i-][j - add].b + b[k]};
                     }
                 }
             }
         }
         set<int> S;
         int aa, bb;
         for(int add=;add<=;add++)
         {
             if(dp[m][-add].now == - && dp[m][+add].now == -) continue;
             int temp = ;
             if(dp[m][-add].now != -)
             {
                 temp = dp[m][-add].val;
                 S = get(-add);
                 aa = dp[m][-add].a, bb = dp[m][-add].b;
             }
             if(dp[m][+add].now != -)
             {
                 if(dp[m][+add].val > temp)
                 {
                     S = get(+add);
                     aa = dp[m][+add].a, bb = dp[m][+add].b;
                 }
             }
             break;
         }
         printf("Jury #%d\n",kase++);
         printf("Best jury has value %d for prosecution and value %d for defence:\n",aa,bb);
         for(set<int>::iterator it=S.begin();it!=S.end();it++) printf(" %d",*it);
         puts("\n");
     }
     return ;
 }