A. Three Strings
time limit per test1 second
memory limit per test256 megabytes
inputstandard input
outputstandard output
You are given three strings a, b and c of the same length n. The strings consist of lowercase English letters only. The i-th letter of a is ai, the i-th letter of b is bi, the i-th letter of c is ci.

For every i (1≤i≤n) you must swap (i.e. exchange) ci with either ai or bi. So in total you’ll perform exactly n swap operations, each of them either ci↔ai or ci↔bi (i iterates over all integers between 1 and n, inclusive).

For example, if a is “code”, b is “true”, and c is “help”, you can make c equal to “crue” taking the 1-st and the 4-th letters from a and the others from b. In this way a becomes “hodp” and b becomes “tele”.

Is it possible that after these swaps the string a becomes exactly the same as the string b?

Input
The input consists of multiple test cases. The first line contains a single integer t (1≤t≤100) — the number of test cases. The description of the test cases follows.

The first line of each test case contains a string of lowercase English letters a.

The second line of each test case contains a string of lowercase English letters b.

The third line of each test case contains a string of lowercase English letters c.

It is guaranteed that in each test case these three strings are non-empty and have the same length, which is not exceeding 100.

Output
Print t lines with answers for all test cases. For each test case:

If it is possible to make string a equal to string b print “YES” (without quotes), otherwise print “NO” (without quotes).

You can print either lowercase or uppercase letters in the answers.

Example
inputCopy
4
aaa
bbb
ccc
abc
bca
bca
aabb
bbaa
baba
imi
mii
iim
outputCopy
NO
YES
YES
NO
Note
In the first test case, it is impossible to do the swaps so that string a becomes exactly the same as string b.

In the second test case, you should swap ci with ai for all possible i. After the swaps a becomes “bca”, b becomes “bca” and c becomes “abc”. Here the strings a and b are equal.

In the third test case, you should swap c1 with a1, c2 with b2, c3 with b3 and c4 with a4. Then string a becomes “baba”, string b becomes “baba” and string c becomes “abab”. Here the strings a and b are equal.

In the fourth test case, it is impossible to do the swaps so that string a becomes exactly the same as string b.

题意：给三个字符串abc 长度len一样 对于每个位置，必须进行ai和ci交换 或者bi和ci进行交换，这样一共进行了len次交换，你可以选择ci和ai还是bi交换，问是不是存在操作 使得字符串a和b相等

思路：一定要交换，所以我们判断a_i<mark>c_i 或者 b_i</mark>c_i 都满足 就是YES 不然就是NO
a_i<mark>c_i 我们可以c_i和b_i交换 b_i</mark>c_i 我们可以a_i和c_i交换

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define me(a,x) memset(a,x,sizeof a)
#define pb(a) push_back(a)
#define pa pair<int,int>
#define fi first
#define se second
int main()
{
 
     int t;cin>>t;
     while(t--){
 
       string a,b,c;
       cin>>a>>b>>c;
       int len=a.size();
       int flag=0;
       for(int i=0;i<len;i++){
 
          if( b[i]==c[i] || a[i]==c[i]) continue;
          else {flag=1;break;}
 
       }
       puts(!flag?"YES":"NO");
     }
   return 0;
}