POJ 3620 Avoid The Lakes【DFS找联通块】

Avoid The Lakes

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 6826		Accepted: 3637

Description

Farmer John's farm was flooded in the most recent storm, a fact only aggravated by the information that his cows are deathly afraid of water. His insurance agency will only repay him, however, an amount depending on the size of the largest "lake" on his farm.

The farm is represented as a rectangular grid with N (1 ≤ N ≤ 100) rows andM (1 ≤M ≤ 100) columns. Each cell in the grid is either dry or submerged, and exactlyK (1 ≤K ≤N × M) of the cells are submerged. As one would expect, a lake has a central cell to which other cells connect by sharing a long edge (not a corner). Any cell that shares a long edge with the central cell or shares a long edge with any connected cell becomes a connected cell and is part of the lake.

Input

* Line 1: Three space-separated integers: N, M, and K
* Lines 2..K+1: Line i+1 describes one submerged location with two space separated integers that are its row and column:R andC

Output

* Line 1: The number of cells that the largest lake contains.　

Sample Input

3 4 5
3 2
2 2
3 1
2 3
1 1

问题描述

农民约翰的农场被最近的一场暴风雨(storm)所淹没(flooded)，事实却依旧恶化(aggravated)，由于他的牛怕水，已经快死了。但是，他的保险公司(insurance agency)将会根据他农场中最大水池的大小来赔偿。

他的农场可视作一个N行(rows)M列(columns)的矩形(rectangular)网格(grid)。每格(cell)不是干的就是在水里的(submerged)，准确来说，有K(1 ≤K ≤N ×M)格是湿的，

输入

第一行：三个分开的整数，N，M和K

第二行...第K+1行：第i+1行为湿地坐标，横坐标R和纵坐标C

输出：

第一行：最大湖泊的格子数