AtCoder Beginner Contest 177
F
I hate Shortest Path Problem
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原题
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Problem Statement

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There is a grid of squares with $H+1$ horizontal rows and $W$ vertical columns.

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You will start at one of the squares in the top row and repeat moving one square right or down. However, for each integer $i$ from $1$ through $H$, you cannot move down from the $A_i$-th, $(A_i + 1)$-th, $\ldots$, $B_i$-th squares from the left in the $i$-th row from the top.

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For each integer $k$ from $1$ through $H$, find the minimum number of moves needed to reach one of the squares in the $(k+1)$-th row from the top. (The starting square can be chosen individually for each case.) If, starting from any square in the top row, none of the squares in the $(k+1)$-th row can be reached, print -1 instead.

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Constraints

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  • $1 \leq H,W \leq 2\times 10^5$
  • $1 \leq A_i \leq B_i \leq W$
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Input

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Input is given from Standard Input in the following format:

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H W
A_1 B_1
A_2 B_2
:
A_H B_H

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Output

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Print $H$ lines. The $i$-th line should contain the answer for the case $k=i$.

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样例

Input #1
4 4
2 4
1 1
2 3
2 4
Output #1
1
3
6
-1
Let $(i,j)$ denote the square at the $i$-th row from the top and $j$-th column from the left. For $k=1$, we need one move such as $(1,1)$ → $(2,1)$. For $k=2$, we need three moves such as $(1,1)$ → $(2,1)$ → $(2,2)$ → $(3,2)$. For $k=3$, we need six moves such as $(1,1)$ → $(2,1)$ → $(2,2)$ → $(3,2)$ → $(3,3)$ → $(3,4)$ → $(4,4)$. For $k=4$, it is impossible to reach any square in the fifth row from the top.
题目信息
题号
abc177_f
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。