由 --- 於 星期五 四月 25, 2003 8:57 pm
1, 2, 3,...25 ,即a1 到e5 是1到25的一個permutation,
max(a1..a5)+1=min(b1...b5)
max(b1..b5)+1=min(c1...c5)
max(c1..c5)+1=min(d1...d5)
max(d1..d5)+1=min(e1...e5)
==> {a1,a2,a3,a4,a5}<{b1,b2,b3,b4,b5}<...<{e1,e2,e3,e4,e5}
==> {a1,a2,a3,a4,a5}={1,2,3,4,5}
{b1,b2,b3,b4,b5}={6,7,8,9,10}
...
{e1,e2,e3,e4,e5}={21,22,23,24,25}
but a2+a3+a4+a5 < 1+2+3+4+5 < b1+c1+d1+e1
so, no solution