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According to the Wikipedia‘s article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970."
Given a board with m by n cells, each cell has an initial state live (1) or dead (0). Each cell interacts with its eight neighbors (horizontal, vertical, diagonal) using the following four rules (taken from the above Wikipedia article):
Write a function to compute the next state (after one update) of the board given its current state.
Follow up:
生命游戏，要求in-place，即只在board数组中处理，不要开额外的数组空间。
整理一下规则：
1. 邻居小于2个或者大于3个就会死；
2. 邻居等于2个，状态不变，原来是什么还是什么；
3. 邻居等于3个，存活，不管原来是什么状态。
in-place主要需要解决一个问题，处理一个cell的时候，不能根据改变后的状态判断，要依据原始的状态。
第一轮处理，无非就是4种情况：0 -> 0, 1 -> 1, 0 -> 1, 1 -> 0。
其中0 -> 0, 1 -> 1没有问题，我们把0 -> 1记成2， 1 -> 0记成3。
在判断邻居的时候1和3都认为是活着的。
第二轮循环把所有的2换成1,3换成0。
1 /** 2 * @param {number[][]} board 3 * @return {void} Do not return anything, modify board in-place instead. 4 */ 5 var gameOfLife = function(board) { 6 var i, j; 7 for(i = 0; i < board.length; i++){ 8 for(j = 0; j < board[i].length; j++){ 9 var curr = board[i][j]; 10 var neighbors = countNeighbors(i, j); 11 if(neighbors < 2 || neighbors > 3){ 12 if(curr === 1){ 13 board[i][j] = 3; 14 } 15 }else if(neighbors === 3){ 16 if(curr === 0){ 17 board[i][j] = 2; 18 } 19 } 20 } 21 } 22 for(i = 0; i < board.length; i++){ 23 for(j = 0; j < board[i].length; j++){ 24 if(board[i][j] === 2){ 25 board[i][j] = 1; 26 }else if(board[i][j] === 3){ 27 board[i][j] = 0; 28 } 29 } 30 } 31 32 33 function countNeighbors(i, j){ 34 var count = 0; 35 count += isAlive(i, j - 1); count += isAlive(i, j + 1); 36 count += isAlive(i - 1, j - 1); count += isAlive(i - 1, j); count += isAlive(i - 1, j + 1); 37 count += isAlive(i + 1, j - 1); count += isAlive(i + 1, j); count += isAlive(i + 1, j + 1); 38 return count; 39 } 40 function isAlive(i, j){ 41 if(!board[i] || !board[i][j]){ 42 return 0; 43 } 44 var cell = board[i][j]; 45 if(cell === 1 || cell === 3){ 46 return 1; 47 } 48 return 0; 49 } 50 };
[LeetCode][JavaScript]Game of Life
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原文地址：http://www.cnblogs.com/Liok3187/p/4868599.html
