KILLER
Time Limit: 1 Sec Memory Limit: 128 MB
Submissions: 519 Solved: 147
Description
There are n Killers in a city.Each killer want to kill a killer(maybe a suicide) and if A want to kill B , there will not be another killer want to kill B. Killers kill their aim by turn and we ensure that in the end ,there will be at most one killer still alive. If there is one killer not be killed in the end, he will be the king of killer.Can you tell me the number of killer who can be the king of killer?
Input
The first line is an integer T indicating the number of test cases.
Next T block, each block is a test case.
First line of each block is a integer N ( 1 <= N <= 100000 )
Followed by N lines, each line is two integers A B , indicating that A will kill B.
Output
The number of killer who can be the king of killer.
Sample Input
2
2
1 2
2 1
1
1 1
Sample Output
2
0
1
#include <iostream>
2#include <cstdio>
3
4using namespace std;
5
6
int main() 
{
7
int td, n, ans, a, b;
8 scanf( "%d", &td );
9
while ( td-- > 0 ) {
10 scanf( "%d", &n );
11 ans = n;
12 while ( n-- > 0 ) {
13 scanf( "%d%d", &a, &b );
14 if ( a == b ) {
15 --ans;
16
}
17 }
18 printf( "%d\n", ans );
19 }
20 return 0;
21
}
22