Codeforces Round #Pi (Div. 2)
E
President and Roads
Codeforces
2200
原题
← DF →
翻译中…

Berland has $*n*$ cities, the capital is located in city $*s*$, and the historic home town of the President is in city $*t*$ ($*s* ≠ *t*$). The cities are connected by one-way roads, the travel time for each of the road is a positive integer.

翻译中…

Once a year the President visited his historic home town $*t*$, for which his motorcade passes along some path from $*s*$ to $*t*$ (he always returns on a personal plane). Since the president is a very busy man, he always chooses the path from $*s*$ to $*t*$, along which he will travel the fastest.

翻译中…

The ministry of Roads and Railways wants to learn for each of the road: whether the President will definitely pass through it during his travels, and if not, whether it is possible to repair it so that it would definitely be included in the shortest path from the capital to the historic home town of the President. Obviously, the road can not be repaired so that the travel time on it was less than one. The ministry of Berland, like any other, is interested in maintaining the budget, so it wants to know the minimum cost of repairing the road. Also, it is very fond of accuracy, so it repairs the roads so that the travel time on them is always a positive integer.

翻译中…

Input

翻译中…

The first lines contain four integers $*n*$, $*m*$, $*s*$ and $*t*$ ($2 ≤ *n* ≤ 10^{5}; 1 ≤ *m* ≤ 10^{5}; 1 ≤ *s*, *t* ≤ *n*$) — the number of cities and roads in Berland, the numbers of the capital and of the Presidents' home town ($*s* ≠ *t*$).

翻译中…

Next $*m*$ lines contain the roads. Each road is given as a group of three integers $*a*_{*i*}, *b*_{*i*}, *l*_{*i*}$ ($1 ≤ *a*_{*i*}, *b*_{*i*} ≤ *n*; *a*_{*i*} ≠ *b*_{*i*}; 1 ≤ *l*_{*i*} ≤ 10^{6}$) — the cities that are connected by the $*i*$-th road and the time needed to ride along it. The road is directed from city $*a*_{*i*}$ to city $*b*_{*i*}$.

翻译中…

The cities are numbered from 1 to $*n*$. Each pair of cities can have multiple roads between them. It is guaranteed that there is a path from $*s*$ to $*t*$ along the roads.

翻译中…

Output

翻译中…

Print $*m*$ lines. The $*i*$-th line should contain information about the $*i*$-th road (the roads are numbered in the order of appearance in the input).

翻译中…

If the president will definitely ride along it during his travels, the line must contain a single word "YES" (without the quotes).

翻译中…

Otherwise, if the $*i*$-th road can be repaired so that the travel time on it remains positive and then president will definitely ride along it, print space-separated word "CAN" (without the quotes), and the minimum cost of repairing.

翻译中…

If we can't make the road be such that president will definitely ride along it, print "NO" (without the quotes).

翻译中…

Note

翻译中…

The cost of repairing the road is the difference between the time needed to ride along it before and after the repairing.

翻译中…

In the first sample president initially may choose one of the two following ways for a ride: $1 → 2 → 4 → 5 → 6$ or $1 → 2 → 3 → 5 → 6$.

翻译中…

样例

Input #1
6 7 1 6
1 2 2
1 3 10
2 3 7
2 4 8
3 5 3
4 5 2
5 6 1
Output #1
YES
CAN 2
CAN 1
CAN 1
CAN 1
CAN 1
YES
InputCopy OutputCopy
Input #2
3 3 1 3
1 2 10
2 3 10
1 3 100
Output #2
YES
YES
CAN 81
InputCopy OutputCopy
Input #3
2 2 1 2
1 2 1
1 2 2
Output #3
YES
NO
InputCopy OutputCopy
题目信息
题号
567E
时间限制
2 s
内存限制
256 MB
标签
DFS 及类似
图论
哈希
最短路

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。