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463. Island Perimeter

时间:2020-07-08 09:14:32      阅读:54      评论:0      收藏:0      [点我收藏+]

标签:complete   connected   mamicode   out   dimens   width   int   dimen   connect   

You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water.

Grid cells are connected horizontally/vertically (not diagonally). The grid is completely surrounded by water, and there is exactly one island (i.e., one or more connected land cells).

The island doesn‘t have "lakes" (water inside that isn‘t connected to the water around the island). One cell is a square with side length 1. The grid is rectangular, width and height don‘t exceed 100. Determine the perimeter of the island.

 

Example:

Input:
[[0,1,0,0],
 [1,1,1,0],
 [0,1,0,0],
 [1,1,0,0]]

Output: 16

Explanation: The perimeter is the 16 yellow stripes in the image below:

技术图片

class Solution {
    public int islandPerimeter(int[][] grid) {
        int res = 0;
        int m = grid.length, n = grid[0].length;
        for(int i = 0; i < m; i++){
            for(int j = 0; j < n; j++){
                if(grid[i][j] == 1){
                    if(i == 0 || grid[i-1][j] == 0) res++;
                    if(i == m-1 || grid[i+1][j] == 0) res++;
                    if(j == 0 || grid[i][j-1] == 0) res++;
                    if(j == n - 1 || grid[i][j+1] == 0) res++;
                }
            }
        }
        return res;
    }
}

 

 

 技术图片

 

 伟大,每个1检测周围4个邻居即可

463. Island Perimeter

标签:complete   connected   mamicode   out   dimens   width   int   dimen   connect   

原文地址:https://www.cnblogs.com/wentiliangkaihua/p/13264559.html

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