* "Copyright (c) 2006 Robert B. Reese ("AUTHOR")"
* All rights reserved.
* (R. Reese, reese@ece.msstate.edu, Mississippi State University)
* IN NO EVENT SHALL THE "AUTHOR" BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE "AUTHOR"
* HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Floyd-Warshall算法描述
1)適用范圍：
a)APSP(All Pairs Shortest Paths)
b)稠密圖效果最佳
c)邊權可正可負
2)算法描述：
a)初始化：dis[u,v]=w[u,v]
b)For k:=1 to n
For i:=1 to n
For j:=1 to n
If dis[i,j]>dis[i,k]+dis[k,j] Then
Dis[I,j]:=dis[I,k]+dis[k,j]
c)算法結(jié)束：dis即為所有點對的最短路徑矩陣
3)算法小結(jié)：此算法簡單有效，由于三重循環(huán)結(jié)構(gòu)緊湊，對于稠密圖，效率要高于執(zhí)行|V|次Dijkstra算法。時間復雜度O(n^3)。
考慮下列變形：如(I,j)∈E則dis[I,j]初始為1,else初始為0，這樣的Floyd算法最后的最短路徑矩陣即成為一個判斷I,j是否有通路的矩陣。更簡單的，我們可以把dis設成boolean類型，則每次可以用“dis[I,j]:=dis[I,j]or(dis[I,k]and dis[k,j])”來代替算法描述中的藍色部分，可以更直觀地得到I,j的連通情況。
DESCRIPTION : BIN to seven segments converter
-- segment encoding
-- a
-- +---+
-- f | | b
-- +---+ <- g
-- e | | c
-- +---+
-- d
-- Enable (EN) active : high
-- Outputs (data_out) active : low
