Magic Spheres
题目描述
Carl is a beginner magician. He has a blue, b violet and c orange magic spheres. In one move he can transform two spheres of the same color into one sphere of any other color. To make a spell that has never been seen before, he needs at least x blue, y violet and z orange spheres. Can he get them (possible, in multiple actions)?
The first line of the input contains three integers a, b and c (0≤a,b,c≤1000000)− the number of blue, violet and orange spheres that are in the magician's disposal.
The second line of the input contains three integers, x, y and z (0≤x,y,z≤1000000)− the number of blue, violet and orange spheres that he needs to get.
If the wizard is able to obtain the required numbers of spheres, print "Yes". Otherwise, print "No".
4 4 0
2 1 2
Yes
5 6 1
2 7 2
No
3 3 3
2 2 2
Yes
In the first sample the wizard has 4 blue and 4 violet spheres. In his first action he can turn two blue spheres into one violet one. After that he will have 2 blue and 5 violet spheres. Then he turns 4 violet spheres into 2 orange spheres and he ends up with 2 blue, 1 violet and 2 orange spheres, which is exactly what he needs.
题目来源：fps-www.educg.net-codeforce-1-2833.xml.zip；FPS 共享题包，题包内第 968 题。保留原作者与原赛事署名。