（模拟）HDU - 5857 Median

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cmath>
 4 #include <algorithm>
 5 
 6 using namespace std;
 7 
 8 const int maxn=100010;
 9 long long num[maxn];
10 
11 int main() {
12     int t;
13     scanf("%d",&t);
14     while(t--) {
15         int n,m;
16         scanf("%d%d",&n,&m);
17         for(int i=1; i<=n; i++) {
18             scanf("%I64d",&num[i]);
19         }
20         for(int i=0; i<m; i++) {
21             double ans=0;
22             int l1,r1,l2,r2;
23             scanf("%d%d%d%d",&l1,&r1,&l2,&r2);
24             if(l1>l2||(l1==l2&&r1>r2)) {
25                 swap(l1,l2);
26                 swap(r1,r2);
27             }
28             if(l1<=l2&&r1>=r2) {
29                 swap(r1,r2);
30             }
31             int len1=r1-l1+1;
32             int len2=r2-l2+1;
33             int len=len1+len2;
34             if(r1<l2) {
35                 if(len%2==0) {
36                     int half=len/2;
37                     if(len1>half) {
38                         ans=double(num[l1+half-1]+num[l1+half])/2;
39                     } else if(len2>half) {
40                         ans=double(num[r2-half+1]+num[r2-half])/2;
41                     } else if(len1==half) {
42                         ans=double(num[r1]+num[l2])/2;
43                     }
44                 } else {
45                     int half=len/2+1;
46                     if(len1>=half) {
47                         ans=double(num[l1+half-1]);
48                     } else {
49                         ans=double(num[r2-half+1]);
50                     }
51                 }
52             } else {
53                 if(len%2==0) {
54                     int half=len/2;
55                     if(l1+half-1<l2) {
56                         ans=double(num[l1+half-1]+num[l1+half])/2;
57                     } else if(r2-half+1>r1) {
58                         ans=double(num[r2-half+1]+num[r2-half])/2;
59                     } else {
60                         half=half-(l2-l1);
61                         ans=double(num[l2+(int)ceil(double(half)/2)-1]+num[l2+(int)ceil(double(half+1)/2)-1])/2;
62                     }
63                 } else {
64                     int half=len/2+1;
65                     if(l1+half-1<l2) {
66                         ans=double(num[l1+half-1]);
67                     } else if(r2-half+1>r1) {
68                         ans=double(num[r2-half+1]);
69                     } else {
70                         half=half-(l2-l1);
71                         ans=double(num[l2+(int)ceil(double(half)/2)-1]);
72                     }
73                 }
74             }
75             printf("%.1f\n",ans);
76         }
77     }
78     return 0;
79 }