-
G
n . D[i,j] i j.
, ( ).
( ) i j k.
, D[i,j] , .
, D[i, i]=0 i.
for k:=1 to n do
for i:=1 to n do
for j:=1 to n do
d[i, j] = min (d[i, j], d[i, k] + d[k, j]);
, - , - ( , ); , .
, , , , , .., , , - , . , , " ":
const INF=maxlongint;
for k:=1 to n do
for i:=1 to n do
for j:=1 to n do
if (d[i, k] < INF) and (d[k, j] < INF)
d[i, j] = min (d[i, j], d[i, k] + d[k, j]);
"", .
D[i, j] Pr[i,j], k, . i Pr[i, j], Pr[i, j] j. .
, , , .
, - . , ∆, 2∆, 4∆, .
|
|
, :
if (d[i, k] + d[k, j] < d[i, j] - EPS)
d[i, j] = d[i, k] + d[k, j];
!!! EPS . , , 103, EPS=104.
, - .
, i j, , .
, ( ), - (, , ). , , , , -∞.
, , " ". , . i j , t, i j, D[t, t]<0.
, , . , - (,
-INF).