John is
going to a tourist meeting of pupils in his school. In his class he was made
responsible for the tents. At home he found 3 tents: the first one weighs a1 kilograms and accommodates
b1 people, the second tent
weighs a2 kilograms and accommodates
b2 people, the third tent
weighs a3 kilograms and
accommodates b3 people.
There are k pupils in John 's class. Find out if John
can choose tents such that all people can fit in them. Take into account that
the selected tents should weigh no more than w kilograms in total.
Input. The first line contains two
integers: k and w (1 ≤ k ≤
15, 1 ≤ w ≤ 30). The
second line contains six integers: a1,
b1, a2, b2,
a3, b3 (1 ≤ a1,
a2, a3 ≤ 10, 1 ≤ b1, b2,
b3 ≤ 15).
Output. Print YES if it is possible to choose
tents as desired, and NO otherwise.
|
Sample input |
Sample output |
|
10 10 5 5 6
6 4 5 |
YES |
elementary problem – conditional statement
Algorithm
analysis
There are
only three tents, so we can consider all possible alternatives of arranging pupils
in tents. Lets consider all possible arrangements here:
·
only in the first tent;
·
only in the second tent;
·
only in the third tent;
·
only in the first and in the second tent;
·
only in the first and in the third tent;
·
only in the second and in the third tent;
·
in all three tents.
All
described alternatives can be considered with seven conditional statements. Declare
the variable flag, initially set it to 0 (all pupils can not be placed
in tents). Then check the possibility of each of seven placements.
For example
the condition of arranging all the pupils only in the second tent will look
this way:
if ((b2 >= k) && (a2 <=
w)) flag = 1;
The
condition of arranging all the pupils only in the first and in the third tent
will look this way:
if ((b1 + b3 >= k) && (a1 +
a3 <= w)) flag = 1;
Depending
on the variable flag after checking all seven conditions print the answer.
Algorithm realization
Do a
complete search of all possible ways to arrange the pupils in the tents.
scanf("%d %d",&k,&w);
scanf("%d %d %d %d %d %d",&a1,&b1,&a2,&b2,&a3,&b3);
if ((b1 >= k) && (a1 <=
w)) flag = 1;
if ((b2 >= k) && (a2 <=
w)) flag = 1;
if ((b3 >= k) && (a3 <=
w)) flag = 1;
if ((b1 + b2 >= k) && (a1 +
a2 <= w)) flag = 1;
if ((b1 + b3 >= k) && (a1 +
a3 <= w)) flag = 1;
if ((b2 + b3 >= k) && (a2 +
a3 <= w)) flag = 1;
if ((b1 + b2 + b3 >= k) &&
(a1 + a2 + a3 <= w)) flag = 1;
if
(flag) printf("YES\n"); else printf("NO\n");