题目链接
1 /*
2 Name:HDU-2141-Can you find it?
3 Copyright:
4 Author:
5 Date: 2018/4/12 17:15:46
6 Description:
7 暴力，复杂度n^3,不存在的
8 将公式变换为A-B=X-C
9 枚举A-B，复杂度n^2
10 二分查找复杂度O(log2n)，A-B是否存在A-B==X-C
11 */
12 #include <iostream>
13 #include <algorithm>
14 using namespace std;
15 const int MAXN = 1e6 + 10;
16 int a[MAXN], b[MAXN], c[MAXN], ab[MAXN], x[MAXN];
17 int main()
18 {
19 // freopen("in.txt", "r", stdin);
20
21 int l, n, m;
22 int cas = 0;
23 while (cin>>l>>n>>m) {
24 cout<<"Case "<<++cas<<":"<<endl;
25 for (int i=0; i<l; i++) {
26 cin>>a[i];
27 }
28 for (int i=0; i<n; i++) {
29 cin>>b[i];
30 }
31 int k = 0;
32 for (int i=0; i<l; i++) {
33 for(int j=0; j<n; j++) {
34 ab[k++] = a[i] + b[j];
35 }
36 }
37 k--;
38 sort(ab, ab+k);
39 for (int i=0; i<m; i++) {
40 cin>>c[i];
41 }
42 int s;
43 cin>>s;
44 for (int i=0; i<s; ++i) {
45 cin>>x[i];
46 }
47 for (int i=0; i<s; i++) {
48 int flag = 0;
49 for (int j=0; j<m; ++j) {
50 int tmp = x[i] - c[j];
51 if (binary_search(ab, ab+k, tmp) == true) {
52 flag = 1;
53 break;
54 }
55 }
56 if (flag) cout<<"YES"<<endl;
57 else cout<<"NO"<<endl;
58 }
59 }
60 return 0;
61 }
