Problem6287--ABC224 —— B - Mongeness

6287: ABC224 —— B - Mongeness

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Time Limit : 1.000 sec  Memory Limit : 256 MiB

Description

We have a grid with $H$ horizontal rows and $W$ vertical columns, where each square contains an integer. The integer written on the square at the $i$-th row from the top and $j$-th column from the left is $A_{i, j}$.
Determine whether the grid satisfies the condition below.
$A_{i_1, j_1} + A_{i_2, j_2} \leq A_{i_2, j_1} + A_{i_1, j_2}$ holds for every quadruple of integers $(i_1, i_2, j_1, j_2)$ such that $1 \leq i_1 < i_2 \leq H$ and $1 \leq j_1 < j_2 \leq W$.

Input

Input is given from Standard Input in the following format:
$H\ W$
$A_{1, 1}\ A_{1, 2}\ \cdots\ A_{1, W}$
$A_{2, 1}\ A_{2, 2}\ \cdots\ A_{2, W}$
$\vdots$
$A_{H, 1}\ A_{H, 2}\ \cdots\ A_{H, W}$

Output

If the grid satisfies the condition in the Problem Statement, print Yes; otherwise, print No.

Constraints

$2≤H,W≤50$
$1 \leq A_{i, j} \leq 10^9$
All values in input are integers.

Sample 1 Input

3 3
2 1 4
3 1 3
6 4 1

Sample 1 Output

Yes
There are nine quadruples of integers $(i_1, i_2, j_1, j_2)$ such that $1 \leq i_1 < i_2 \leq H$ and $1 \leq j_1 < j_2 \leq W$. For all of them, $A_{i_1, j_1} + A_{i_2, j_2} \leq A_{i_2, j_1} + A_{i_1, j_2}$ holds. Some examples follow.
  • For $(i_1, i_2, j_1, j_2) = (1, 2, 1, 2)$, we have $A_{i_1, j_1} + A_{i_2, j_2} = 2 + 1 \leq 3 + 1 = A_{i_2, j_1} + A_{i_1, j_2}$.
  • For $(i_1, i_2, j_1, j_2) = (1, 2, 1, 3)$, we have $A_{i_1, j_1} + A_{i_2, j_2} = 2 + 3 \leq 3 + 4 = A_{i_2, j_1} + A_{i_1, j_2}$.
  • For $(i_1, i_2, j_1, j_2) = (1, 2, 2, 3)$, we have $A_{i_1, j_1} + A_{i_2, j_2} = 1 + 3 \leq 1 + 4 = A_{i_2, j_1} + A_{i_1, j_2}$.
  • For $(i_1, i_2, j_1, j_2) = (1, 3, 1, 2)$, we have $A_{i_1, j_1} + A_{i_2, j_2} = 2 + 4 \leq 6 + 1 = A_{i_2, j_1} + A_{i_1, j_2}$.
  • For $(i_1, i_2, j_1, j_2) = (1, 3, 1, 3)$, we have $A_{i_1, j_1} + A_{i_2, j_2} = 2 + 1 \leq 6 + 4 = A_{i_2, j_1} + A_{i_1, j_2}$.
We can also see that the property holds for the other quadruples: $(i_1, i_2, j_1, j_2) = (1, 3, 2, 3), (2, 3, 1, 2), (2, 3, 1, 3), (2, 3, 2, 3)$.
Thus, we should print Yes.

Sample 2 Input

2 4
4 3 2 1
5 6 7 8

Sample 2 Output

No
We should print No because the condition is not satisfied.
This is because, for example, we have $A_{i_1, j_1} + A_{i_2, j_2} = 4 + 8 > 5 + 1 = A_{i_2, j_1} + A_{i_1, j_2}$.

Source/Category

AtCoder_ABC 100.224.ABC224