zoj 3469 dp 记忆化搜索

/*zoj 3469  记忆化dp；  dp[i][j][0-1]表示已经送过左边的i个和右边的j个，01分别表示当前停在那里key2:当前要走的距离也是其之后要送的走的距离·参照大牛写的，orz，dp的路还很长啊*/#include<iostream>#include<cstring>#include<algorithm>#include<cstdio>//#define min(a,b) ((a)<(b))?((a):(b))#define inf 0x3ffffffffffusing namespace std;struct abc{int x;int b; }lef[1010],righ[1010];int l,r;bool cmp(abc a,abc b){return a.x<b.x;}long long dp[1010][1010][2];//int len[1010][1010][2];long long  getdp(int i,int j,int k){if(dp[i][j][k]!=-1)return dp[i][j][k];long long ans=inf;if(k==0)//在左边{if(i!=0){int tmp=lef[i].b+righ[j+1].b;//所有还未走的的人的愤怒值之和ans=min(ans,getdp(i-1,j,0)+(lef[i].x-lef[i-1].x)*tmp);ans=min(ans,getdp(i-1,j,1)+(lef[i].x+righ[j].x)*tmp);}}else {if(j!=0){int tmp=lef[i+1].b+righ[j].b;ans=min(ans,getdp(i,j-1,1)+(righ[j].x-righ[j-1].x)*tmp);ans=min(ans,getdp(i,j-1,0)+(lef[i].x+righ[j].x)*tmp);}}return dp[i][j][k]=ans;}int main(){int n,v,x;while(scanf("%d%d%d",&n,&v,&x)!=EOF){int tx,tb;l=r=1;for(int i=0;i<n;i++){scanf("%d%d",&tx,&tb);if(tx>x){righ[r].x=tx-x;righ[r].b=tb;r++;}else {lef[l].x=x-tx;lef[l].b=tb;l++;}}sort(righ+1,righ+r,cmp);sort(lef+1,lef+l,cmp);righ[r].b=0;lef[l].b=0;for(int i=r-1;i>=1;i--){righ[i].b+=righ[i+1].b;}for(int i=l-1;i>=1;i--){lef[i].b+=lef[i+1].b;// cout<<lef[i].b<<' ';}// cout<<endl;for(int i=0;i<=l;i++)for(int j=0;j<=r;j++){dp[i][j][0]=dp[i][j][1]=-1;}dp[0][0][0]=dp[0][0][1]=0;// cout<<"asdasd"<<endl;printf("%lld\n",v*min(getdp(l-1,r-1,0),getdp(l-1,r-1,1)));}return 0;}