;struct data{int x;int a;};data l[1024],r[1024];bool c1(data q,data p){return q.x<p.x;}bool c2(data q,data p){return q.x>p.x;}int main(){int n,i,t,p,ans1,ans2,p1,p2;while(~scanf(“%d\n”,&n)){p1=p2=0;for(i=0;i<n;i++){scanf(“%d%d”,&t,&p);if(t>0){r[p2].x=t;r[p2].a=p;p2++;}else{l[p1].x=t;l[p1].a=p;p1++;}}sort(l,l+p1,c2);sort(r,r+p2,c1);int u1[1024],u2[1024];memset(u1,0,sizeof(u1));memset(u2,0,sizeof(u2));for(ans1=0,i=0;;i++){if(i%2==0){if(i/2>=p1) break;ans1+=l[i/2].a;}else{if(i/2>=p2) break;ans1+=r[i/2].a;}}for(ans2=0,i=0;;i++){if(i%2==1){if(i/2>=p1) break;ans2+=l[i/2].a;}else{if(i/2>=p2) break;ans2+=r[i/2].a;}}printf(“%d\n”,max(ans1,ans2));}return 0;}
，知已知彼，百战百胜。
