CF1552F.Telepanting
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题目描述
An ant moves on the real line with constant speed of 1 unit per second. It starts at 0 and always moves to the right (so its position increases by 1 each second).
There are n portals, the i -th of which is located at position xi and teleports to position yi<xi . Each portal can be either active or inactive. The initial state of the i -th portal is determined by si : if si=0 then the i -th portal is initially inactive, if si=1 then the i -th portal is initially active. When the ant travels through a portal (i.e., when its position coincides with the position of a portal):
- if the portal is inactive, it becomes active (in this case the path of the ant is not affected);
- if the portal is active, it becomes inactive and the ant is instantly teleported to the position yi , where it keeps on moving as normal.
How long (from the instant it starts moving) does it take for the ant to reach the position xn+1 ? It can be shown that this happens in a finite amount of time. Since the answer may be very large, compute it modulo 998244353 .
输入格式
The first line contains the integer n ( 1≤n≤2⋅105 ) — the number of portals.
The i -th of the next n lines contains three integers xi , yi and si ( 1≤yi<xi≤109 , si∈{0,1} ) — the position of the i -th portal, the position where the ant is teleported when it travels through the i -th portal (if it is active), and the initial state of the i -th portal.
The positions of the portals are strictly increasing, that is x1<x2<⋯<xn . It is guaranteed that the 2n integers x1,x2,…,xn,y1,y2,…,yn are all distinct.
输出格式
Output the amount of time elapsed, in seconds, from the instant the ant starts moving to the instant it reaches the position xn+1 . Since the answer may be very large, output it modulo 998244353 .
输入输出样例
输入#1
4 3 2 0 6 5 1 7 4 0 8 1 1
输出#1
23
输入#2
1 454971987 406874902 1
输出#2
503069073
输入#3
5 243385510 42245605 0 644426565 574769163 0 708622105 208990040 0 786625660 616437691 0 899754846 382774619 0
输出#3
899754847
输入#4
5 200000000 100000000 1 600000000 400000000 0 800000000 300000000 0 900000000 700000000 1 1000000000 500000000 0
输出#4
3511295
说明/提示
Explanation of the first sample: The ant moves as follows (a curvy arrow denotes a teleporting, a straight arrow denotes normal movement with speed 1 and the time spent during the movement is written above the arrow). $$$$ 0 \stackrel{6}{\longrightarrow} 6 \leadsto 5 \stackrel{3}{\longrightarrow} 8 \leadsto 1 \stackrel{2}{\longrightarrow} 3 \leadsto 2 \stackrel{4}{\longrightarrow} 6 \leadsto 5 \stackrel{2}{\longrightarrow} 7 \leadsto 4 \stackrel{2}{\longrightarrow} 6 \leadsto 5 \stackrel{4}{\longrightarrow} 9 $$ Notice that the total time is 6+3+2+4+2+2+4=23 .
Explanation of the second sample: The ant moves as follows (a curvy arrow denotes a teleporting, a straight arrow denotes normal movement with speed 1 and the time spent during the movement is written above the arrow). $$ 0 \stackrel{454971987}{\longrightarrow} 454971987 \leadsto 406874902 \stackrel{48097086}{\longrightarrow} 454971988 $$ Notice that the total time is 454971987+48097086=503069073 .
Explanation of the third sample: Since all portals are initially off, the ant will not be teleported and will go straight from 0 to x_n+1=899754846+1=899754847$$.