zoukankan      html  css  js  c++  java
  • Island Perimeter

    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:

    [[0,1,0,0],
     [1,1,1,0],
     [0,1,0,0],
     [1,1,0,0]]
    
    Answer: 16
    Explanation: The perimeter is the 16 yellow stripes in the image below:
    

    分析:计算给出图形的周长,不存在孤岛。

    思路:统计相邻岛屿数分别为0,1,2,3的个数。计算公式:s0*4+s1*3+s2*2+s4*1

    JAVA CODE:

    class Solution {
        public int islandPerimeter(int[][] grid) {
            int s0 = 0, s1 = 0, s2 = 0, s3 = 0;
            for(int i = 0; i < grid.length; i++){
                for(int j = 0; j < grid[0].length; j++){
                    int m = grid[i][j];
                    if(m == 0)
                        continue;
                    int s = 0;
                    if(i > 0 && grid[i - 1][j] == 1)
                        s++;
                    if(i < grid.length - 1 && grid[i + 1][j] == 1)
                        s++;
                    if(j > 0 && grid[i][j - 1] == 1)
                        s++;
                    if(j < grid[0].length - 1 && grid[i][j + 1] == 1)
                        s++;
                    if(s == 0)
                        s0++;
                    if(s == 1)
                        s1++;
                    if(s == 2)
                        s2++;
                    if(s == 3)
                        s3++;
                }
            }
            return s0 * 4 + s1 * 3 + s2 * 2 + s3 * 1;
        }
    }
  • 相关阅读:
    数据结构 trie 树 入门练手 POJ 3630 Phone List
    回溯法求 1~n 的排列
    POJ 1988 Cube Stacking (并查集,节点到根节点的距离题目)
    Ubuntu下的截图软件
    git使用方法
    在Linux下安装ADT
    在Linux下安装Android SDK
    在Linux下安装Java JDK
    研发项目风险因素差异性
    关于C#的partial修饰符
  • 原文地址:https://www.cnblogs.com/baichangfu/p/7456374.html
Copyright © 2011-2022 走看看