BNUOJ 36005 Chemical Reaction

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define INF 0x3f3f3f3f
15 #define pii pair<int,int>
16 using namespace std;
17 const int maxn = 500100;
18 struct node {
19     int x,y,id,minv,maxv;
20     node(int tx = 0,int ty = 0,int tz = 0) {
21         x = tx;
22         y = ty;
23         id = tz;
24     }
25   bool operator< (const node &t)const{
26         return y < t.y;
27     }
28 };
29 node pa[maxn],pb[maxn];
30 int ca,cb,u[maxn],v[maxn],T,n;
31 int bsearch(int lt,int rt,int val,node *d){
32     int ans = rt+1;
33     while(lt <= rt){
34         int mid = (lt+rt)>>1;
35         if(d[mid].y >= val){
36             ans = mid;
37             rt = mid-1;
38         }else lt = mid+1;
39     }
40     return ans;
41 }
42 int main() {
43     scanf("%d",&T);
44     while(T--) {
45         scanf("%d",&n);
46         for(int i = ca = cb = 0; i < n; ++i) {
47             scanf("%d %d",u+i,v+i);
48             if(v[i] < 0) pa[ca++] = node(u[i],-v[i],i);
49             else pb[cb++] = node(u[i],v[i],i);
50         }
51         sort(pa,pa+ca);
52         sort(pb,pb+cb);
53         if(ca) pa[ca-1].minv = pa[ca-1].maxv = pa[ca-1].x;
54         if(cb) pb[cb-1].minv = pb[cb-1].maxv = pb[cb-1].x;
55         for(int i = ca-2; i >= 0; --i) {
56             pa[i].minv = min(pa[i].x,pa[i+1].minv);
57             pa[i].maxv = max(pa[i].x,pa[i+1].maxv);
58         }
59         for(int i = cb-2; i >= 0; --i) {
60             pb[i].minv = min(pb[i].x,pb[i+1].minv);
61             pb[i].maxv = max(pb[i].x,pb[i+1].maxv);
62         }
63         int ans = -INF;
64         for(int i = 0; i < n; ++i) {
65             int idx = INF;
66             if(ca) {
67                 idx = bsearch(0,ca-1,abs(v[i]),pa);
68                 if(idx < ca && pa[idx].id == i) idx++;
69                 if(idx < ca) {
70                     ans = max(ans,-abs(u[i] - pa[idx].minv)*v[i]);
71                     ans = max(ans,-abs(u[i] - pa[idx].maxv)*v[i]);
72                     ans = max(ans,-abs(pa[idx].minv - u[i])*v[i]);
73                     ans = max(ans,-abs(pa[idx].maxv - u[i])*v[i]);
74                 }
75             }
76             if(cb) {
77                 idx = bsearch(0,cb-1,abs(v[i]),pb);
78                 if(idx < cb && pb[idx].id == i) idx++;
79                 if(idx < cb) {
80                     ans = max(ans,abs(u[i] - pb[idx].minv)*v[i]);
81                     ans = max(ans,abs(u[i] - pb[idx].maxv)*v[i]);
82                     ans = max(ans,abs(pb[idx].minv - u[i])*v[i]);
83                     ans = max(ans,abs(pb[idx].maxv - u[i])*v[i]);
84                 }
85             }
86         }
87         printf("%d\n",ans);
88 
89     }
90     return 0;
91 }