264C - Choosing Balls DP

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总结：if elese if 还是掌握不够

#include <iostream>#include <cstdio>#define LL long long#define eps -1e17const int LMT=100003;//连接因子的判断啊using namespace std;LL v[LMT];int c[LMT];LL dp[LMT];int main(){   int n,fir,sec,q;   LL a,b,tem,geta,getb,ans=0;   scanf("%d%d",&n,&q);   for(int i=1;i<=n;i++)scanf("%I64d",&v[i]);   for(int i=1;i<=n;i++)scanf("%d",&c[i]);   while(q--)   {       scanf("%I64d%I64d",&a,&b);       ans=0;       for(int i=0;i<=n;i++)       dp[i]=eps;       dp[0]=0;       fir=0;sec=-1;       for(int i=1;i<=n;i++)       {           geta=getb=eps;tem=eps;           if(dp[c[i]]!=eps)tem=v[i]*a+dp[c[i]];           if(fir==c[i])geta=v[i]*a+dp[fir];           else geta=v[i]*b+dp[fir];           if(fir==c[i]&&sec!=-1)           {               if(sec==c[i])getb=v[i]*a+dp[sec];               else getb=v[i]*b+dp[sec];           }           tem=max(max(geta,getb),tem);           dp[c[i]]=max(dp[c[i]],tem);           if(tem>dp[fir]&&c[i]!=fir)//这里仔细啊，条件一定要精确           {               sec=fir;               fir=c[i];           }           else if(fir!=c[i]&&(sec==-1||tem>dp[sec]))sec=c[i];           ans=max(ans,tem);       }       cout<<ans<<endl;   }    return 0;}