From 6a201720030faa7a70abcc313c1aa756245f3329 Mon Sep 17 00:00:00 2001 From: AronJudge <2286381138@qq.com> Date: Sat, 20 Aug 2022 10:38:58 +0800 Subject: [PATCH 1/3] =?UTF-8?q?463=20=E5=B2=9B=E5=B1=BF=E7=9A=84=E5=91=A8?= =?UTF-8?q?=E9=95=BF?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 更新Java的方法二 --- problems/0463.岛屿的周长.md | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/problems/0463.岛屿的周长.md b/problems/0463.岛屿的周长.md index ea038140..3dc69f20 100644 --- a/problems/0463.岛屿的周长.md +++ b/problems/0463.岛屿的周长.md @@ -118,6 +118,27 @@ class Solution { return res; } } + +// 解法二 +class Solution { + public int islandPerimeter(int[][] grid) { + // 计算岛屿的周长 + // 方法二 : 遇到相邻的陆地总周长就-2 + int landSum = 0; // 陆地数量 + int cover = 0; // 相邻陆地数量 + for (int i = 0; i < grid.length; i++) { + for (int j = 0; j < grid[0].length; j++) { + if (grid[i][j] == 1) { + landSum++; + // 统计上面和左边的相邻陆地 + if(i - 1 >= 0 && grid[i-1][j] == 1) cover++; + if(j - 1 >= 0 && grid[i][j-1] == 1) cover++; + } + } + } + return landSum * 4 - cover * 2; + } +} ``` Python： From b2534f7993018e497670e05fdf258830a1f4b69b Mon Sep 17 00:00:00 2001 From: AronJudge <2286381138@qq.com> Date: Sat, 20 Aug 2022 16:50:29 +0800 Subject: [PATCH 2/3] =?UTF-8?q?05=20=E6=9C=80=E9=95=BF=E5=9B=9E=E6=96=87?= =?UTF-8?q?=E5=AD=90=E4=B8=B2?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 更新Java动态绘画方法， 之前的根本就不是这个题 --- problems/0005.最长回文子串.md | 44 ++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 13 deletions(-) diff --git a/problems/0005.最长回文子串.md b/problems/0005.最长回文子串.md index d53acf63..893525d2 100644 --- a/problems/0005.最长回文子串.md +++ b/problems/0005.最长回文子串.md @@ -263,21 +263,39 @@ public: Java： ```java -public int[] twoSum(int[] nums, int target) { - int[] res = new int[2]; - if(nums == null || nums.length == 0){ - return res; - } - Map map = new HashMap<>(); - for(int i = 0; i < nums.length; i++){ - int temp = target - nums[i]; - if(map.containsKey(temp)){ - res[1] = i; - res[0] = map.get(temp); +// 双指针 动态规划 +class Solution { + public String longestPalindrome(String s) { + if (s.length() == 0 || s.length() == 1) return s; + int length = 1; + int index = 0; + boolean[][] palindrome = new boolean[s.length()][s.length()]; + for (int i = 0; i < s.length(); i++) { + palindrome[i][i] = true; } - map.put(nums[i], i); + + for (int L = 2; L <= s.length(); L++) { + for (int i = 0; i < s.length(); i++) { + int j = i + L - 1; + if (j >= s.length()) break; + + if (s.charAt(i) != s.charAt(j)) { + palindrome[i][j] = false; + } else { + if (j - i < 3) { + palindrome[i][j] = true; + } else { + palindrome[i][j] = palindrome[i + 1][j - 1]; + } + } + if (palindrome[i][j] && j - i + 1 > length) { + length = j - i + 1; + index = i; + } + } + } + return s.substring(index, index + length); } - return res; } ``` From a97a7ef2ece2b73f87c196e01037508d1f197deb Mon Sep 17 00:00:00 2001 From: AronJudge <2286381138@qq.com> Date: Sat, 20 Aug 2022 16:50:29 +0800 Subject: [PATCH 3/3] =?UTF-8?q?05=20=E6=9C=80=E9=95=BF=E5=9B=9E=E6=96=87?= =?UTF-8?q?=E5=AD=90=E4=B8=B2?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 更新Java动态规划方法 之前的根本就不是这个题 --- problems/0005.最长回文子串.md | 43 ++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 13 deletions(-) diff --git a/problems/0005.最长回文子串.md b/problems/0005.最长回文子串.md index d53acf63..b9b568ab 100644 --- a/problems/0005.最长回文子串.md +++ b/problems/0005.最长回文子串.md @@ -263,21 +263,38 @@ public: Java： ```java -public int[] twoSum(int[] nums, int target) { - int[] res = new int[2]; - if(nums == null || nums.length == 0){ - return res; - } - Map map = new HashMap<>(); - for(int i = 0; i < nums.length; i++){ - int temp = target - nums[i]; - if(map.containsKey(temp)){ - res[1] = i; - res[0] = map.get(temp); +// 双指针 动态规划 +class Solution { + public String longestPalindrome(String s) { + if (s.length() == 0 || s.length() == 1) return s; + int length = 1; + int index = 0; + boolean[][] palindrome = new boolean[s.length()][s.length()]; + for (int i = 0; i < s.length(); i++) { + palindrome[i][i] = true; } - map.put(nums[i], i); + + for (int L = 2; L <= s.length(); L++) { + for (int i = 0; i < s.length(); i++) { + int j = i + L - 1; + if (j >= s.length()) break; + if (s.charAt(i) != s.charAt(j)) { + palindrome[i][j] = false; + } else { + if (j - i < 3) { + palindrome[i][j] = true; + } else { + palindrome[i][j] = palindrome[i + 1][j - 1]; + } + } + if (palindrome[i][j] && j - i + 1 > length) { + length = j - i + 1; + index = i; + } + } + } + return s.substring(index, index + length); } - return res; } ```