AtCoder Beginner Contest 204
E
Rush Hour 2
AtCoder
⌀ 1710
原题
← DF →
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Problem Statement

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The Republic of AtCoder has $N$ cities and $M$ roads.

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The cities are numbered $1$ through $N$, and the roads are numbered $1$ through $M$. Road $i$ connects City $A_i$ and City $B_i$ bidirectionally.

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There is a rush hour in the country that peaks at time $0$. If you start going through Road $i$ at time $t$, it will take $C_i+ \left\lfloor \frac{D_i}{t+1} \right\rfloor$ time units to reach the other end. ($\lfloor x\rfloor$ denotes the largest integer not exceeding $x$.)

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Takahashi is planning to depart City $1$ at time $0$ or some integer time later and head to City $N$.

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Print the earliest time when Takahashi can reach City $N$ if he can stay in each city for an integer number of time units. It can be proved that the answer is an integer under the Constraints of this problem.

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If City $N$ is unreachable, print -1 instead.

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Constraints

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  • $2 \leq N \leq 10^5$
  • $0 \leq M \leq 10^5$
  • $1 \leq A_i,B_i \leq N$
  • $0 \leq C_i,D_i \leq 10^9$
  • All values in input are integers.
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Input

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Input is given from Standard Input in the following format:

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N M
A_1 B_1 C_1 D_1
\vdots
A_M B_M C_M D_M

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Output

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Print an integer representing the earliest time when Takahashi can reach City $N$, or -1 if City $N$ is unreachable.

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样例

Input #1
2 1
1 2 2 3
Output #1
4
We will first stay in City $1$ until time $1$. Then, at time $1$, we will start going through Road $1$, which will take $2+\left\lfloor \frac{3}{1+1} \right\rfloor = 3$ time units before reaching City $2$ at time $4$. It is impossible to reach City $2$ earlier than time $4$.
Input #2
2 3
1 2 2 3
1 2 2 1
1 1 1 1
Output #2
3
There may be multiple roads connecting the same pair of cities, and a road going from a city to the same city.
Input #3
4 2
1 2 3 4
3 4 5 6
Output #3
-1
There may be no path from City $1$ to City $N$.
Input #4
6 9
1 1 0 0
1 3 1 2
1 5 2 3
5 2 16 5
2 6 1 10
3 4 3 4
3 5 3 10
5 6 1 100
4 2 0 110
Output #4
20
题目信息
题号
abc204_e
时间限制
2 s
内存限制
1024 MB

题面与样例版权归 AtCoder 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。