差分约束系统（转）
https://blog.csdn.net/my_sunshine26/article/detail …
J – Invitation Cards（双向最短路）
In the age of television, not many people attend t …
I – Arbitrage
Arbitrage is the use of discrepancies in currency …
H – Cow Contest（Floyd_传递闭包）
N (1 ≤ N ≤ 100) cows, conveniently numbered …
F – Wormholes （B-F判负环回路）
While exploring his many farms, Farmer John …
E – Currency Exchange (B_F变形)
Several currency exchange points are working in ou …
D – Heavy Transportation POJ – 1797
Background Hugo Heavy is happy. After the breakdow …
C – Frogger POJ – 2253
Freddy Frog is sitting on a stone in the mi …
B – Stockbroker Grapevine POJ – 1125
Stockbrokers are known to overreact to rumours. Yo …
A – 最短路 HDU – 2544（模板题）
在每年的校赛里，所有进入决赛的同学都会获得一件很漂亮的t-shirt。但是每当我们的工作人员把上百件 …