AKBAR  Akbar , The great
All of us are familiar with the reign of the great mughal ruler , Akbar. He was always concerned with the prosperity and safety of the people . Therefore to safeguard his kingdom (which consisted of N cities) he wanted to place secret soldiers all over his kingdom so as to protect the people . But since his kingdom is very large therefore he wanted to place them in such a way that every city is protected by one and only one soldier.According to Akbar , this is the optimum placement.
As for these soldiers they can protect multiple cities according to their strengths.
The strength of a particular soldier is defined as the maximum distance upto which a guard can protect a city from its base city(base city is the city assigned to the guard). If there are 3 cities C1, C2 and C3 such that C1 C2 and C2 C3 are connected respectively, if a soldier with strength 1 is placed at C2 then all the cities C1, C2 and C3 are protected by that soldier.
Also the kingdom is connected with a network of secret two way roads for faster access only accessible to these soldiers. The length of any road on this network between any two cities is 1 kms .There are R such roads in the kingdom.
He had given this task to birbal to place the soldiers . Birbal didn't wanted to be a fool in front of the king , therefore took the job and placed M soldiers all over the kingdom but he was not very good at mathematics . But since he is very intelligent he somehow places the guards all over the kingdom and now turns to you (who is a genius mathematician ;) ) to check whether his placements are good or not.
Your task is to check if the placements of the soldiers are optimum or not.
INPUT
The input consists of T test cases . Each test case then consists of 3 parts.The first line consists of N, R and M.
the next R lines consists of two numbers A and B denoting the two cities between which a road exists .
the next M lines consists of 2 numbers, city number K and strength S of that particular soldier.
=> strength 0 means it will only guard the city on which it is present .
=> assume every city is accesible from every other city .
CONSTRAINTS
T <= 10;
1 <= N <= 10^6;
N 1 <= R <= min( 10^7 , ( N * (N  1) ) / 2) );
1 <= K <= N;
0 <= S <= 10^6
OUTPUT
print "Yes" if the soldiers are placed optimumly else print "No". (quotes are for clarity)
SAMPLE INPUT
2
3 2 2
1 2
2 3
1 2
2 0
4 5 2
1 4
1 2
1 3
4 2
3 4
2 1
3 0
SAMPLE OUTPUT
No
Yes
WARNING ==> Large input.
hide comments
masterchef2209:
20190301 16:02:55
This question is very poorly worded(maybe intentionally) but it wasted a lot of time.


zarif_2002:
20190210 05:00:08
only bfs. dfs is worthless for some test case. 

adityaxxx:
20190206 16:07:20
@manoj_0786 I think you have to follow Birbal's order sequentially, and, it's not necessary for a soldier to look after every city under his strength. What's necessary here is to see if all the cities here are being protected by sequentially placing the soldiers at mentioned cities. 

manoj_0786:
20181129 07:11:23
ans must be no for this test case:


ankur314:
20180918 06:03:59
Those having problem in first TC, read the words written in bold in problem statement 

s_a_k_s_h_a_m:
20180707 22:38:24
use bfs


soham_12345:
20180703 16:13:30
multipoint bfs 

cyber_sm0ke:
20180701 20:12:28
Can we use DFS to solve the question ?


be1035016:
20180620 14:15:14
good problem.loved it 

codeinfinity:
20180520 09:14:09
in sample test case they have given No as an ans for the first test case.

Added by:  Prayank Mathur 
Date:  20141012 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  own 