num isf scan logs n-2 urn open interval names

第二場

1001 Is Derek lying?

Problem Description Derek and Alfia are good friends.Derek is Chinese,and Alfia is Austrian.This summer holiday,they both participate in the summer camp of Borussia Dortmund.During the summer camp,there will be fan tests at intervals.The test consists of N choice questions and each question is followed by three choices marked “A

” “B” and “C”.Each question has only one correct answer and each question is worth 1 point.It means that if your answer for this question is right,you can get 1point.The total score of a person is the sum of marks for all questions.When the test is over,the computer will tell Derek the total score of him and Alfia

.Then Alfiawill ask Derek the total score of her and he will tell her: “My total score is X,your total score is Y.”But Derek is naughty,sometimes he may lie to her. Here give you the answer that Derek and Alfia made,you should judge whether Derek is lying.If there exists a set of standard answer satisfy the total score that Derek

said,you can consider he is not lying,otherwise he is lying. Input The first line consists of an integer T,represents the number of test cases.
For each test case,there will be three lines.
The first line consists of three integers N,X,Y,the meaning is mentioned above.
The second line consists of N characters,each character is “A” “B” or “C”,which represents the answer of Derek for each question.
The third line consists of N characters,the same form as the second line,which represents the answer of Alfia for each question.
Data Range:1≤N≤80000,0≤X,Y≤N,∑Ti=1N≤300000

Output For each test case,the output will be only a line.
Please print “Lying” if you can make sure that Derek is lying,otherwise please print “Not lying”. Sample Input 2 3 1 3 AAA ABC 5 5 0 ABCBC ACBCB Sample Output Not lying Lying 思路：首先，我們統計出Derek和Alfia答案相同的題目數量k1和答案不同的題目數量k2. 對於兩人答案相同的題目，共有以下兩種情況： a.兩人都對 b.兩人都錯 對於兩人答案不同的題目，共有以下三種情況： c.Derek對Alfia錯 d.Alfia對Derek錯 e.兩人都錯 於是我們可以列出一些方程： k1+k2=n a+b=k1 c+d+e=k2 a+c=x a+d=y 又a,b,c,d,e均為非負整數，且滿足a,b<=k1;c,d,e<=k2，將a,b,d,e全部用c替換後需要同時滿足以下四個條件： 0<=c<=k2 x-y<=c<=k2+x-y (x-y)/2<=c<=(k2+x-y)/2 x-k1<=c<=x 我們只需要判斷這四段區間存不存在公共的整數點，如果存在，則說明Derek沒有說謊；如果不存在，則說明Derek在說謊。

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 #include<cmath>
 6 #include<vector>
 7 #include<set>
 8 #include<string>
 9 #include<sstream>
10 #include<cctype>
11 #include<map> 
12 #include<stack>
13 #include<queue>
14 using namespace std;
15 #define INF 0x3f3f3f3f
16 
17 const int maxn =  80000 + 10;
18 char a[maxn], b[maxn];
19 
20 int main()
21 {
22 //    freopen("input.txt", "r", stdin);
23 //    freopen("output.txt", "w", stdout);
24     int T, n, x, y;
25     scanf("%d", &T);
26     while(T--)
27     {
28         int p = 0, q = 0;
29         scanf("%d%d%d", &n, &x, &y);
30         scanf("%s", a);
31         scanf("%s", b);
32         for(int i = 0; i < n; i++)
33         {
34             if(a[i] == b[i])    p++;
35             else    q++;
36         }
37         if(fabs(x - y) <= q && x + y <= 2 * p + q)
38             printf("Not lying\n");
39         else    printf("Lying\n");
40     }
41     return 0;
42 }

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第二場就做了一題，第三場除了一題簽到題其他題都不會做，被九題十題的高中生草虐，我好菜啊.jpg

今天是暑假第一次這麽早起，加油加油，繼續刷題。

【補題】多校聯合訓練第二場