OJ Board

the O(n^4) algorithm can get AC actually !

but need some tips


sort array first

for( d = N to 1 ) //from higher to lower
for( a = 1 to N )
for( b = a+1 to N )
for( c = b+1 to N )
//do comparison here ..



the tip is put the loop d outside, and from higher to lower

it's very efficeint ...

notice 2 things
1. print "4" digit after demical point
2. "blank line" : print blank line "between" every output case.

sample output code

for(int i=0;i<times;++i){
//calculate the path length
printf ("%.4f\n", path_length);
if( i != times-1) printf("\n"); //dont print \n after the last case ...