From 74afd287d8c69e5aa5c2fc7ef4c6d7b90beb6455 Mon Sep 17 00:00:00 2001 From: kevinding1125 <745518019@qq.com> Date: Fri, 2 Jun 2023 12:19:17 +0800 Subject: [PATCH] =?UTF-8?q?leecode=EF=BC=8Crt=5Fphm=E6=9B=B4=E6=96=B0?= =?UTF-8?q?=E6=9B=B4=E6=96=B0?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../leecode/hot100/second/T65_208_Trie_2.java | 53 +++++++++++++++++++ .../hot100/second/T81_312_MaxCoins.java | 33 +++++++++++- .../hot100/second/T86_394_DecodeString.java | 36 ++++++++++++- .../huawei/{ => T0531}/Question1.java | 2 +- .../huawei/{ => T0531}/Question2.java | 2 +- .../huawei/{ => T0531}/Question3.java | 38 ++++++++++++- 6 files changed, 157 insertions(+), 7 deletions(-) create mode 100644 Leecode/src/main/java/com/markilue/leecode/hot100/second/T65_208_Trie_2.java rename Leecode/src/main/java/com/markilue/leecode/interview/huawei/{ => T0531}/Question1.java (96%) rename Leecode/src/main/java/com/markilue/leecode/interview/huawei/{ => T0531}/Question2.java (95%) rename Leecode/src/main/java/com/markilue/leecode/interview/huawei/{ => T0531}/Question3.java (60%) diff --git a/Leecode/src/main/java/com/markilue/leecode/hot100/second/T65_208_Trie_2.java b/Leecode/src/main/java/com/markilue/leecode/hot100/second/T65_208_Trie_2.java new file mode 100644 index 0000000..b5e6a97 --- /dev/null +++ b/Leecode/src/main/java/com/markilue/leecode/hot100/second/T65_208_Trie_2.java @@ -0,0 +1,53 @@ +package com.markilue.leecode.hot100.second; + +/** + *@BelongsProject: Leecode + *@BelongsPackage: com.markilue.leecode.hot100.second + *@Author: markilue + *@CreateTime: 2023-06-02 11:05 + *@Description: TODO 力扣208 实现Trie(前缀树) + *@Version: 1.0 + */ +public class T65_208_Trie_2 { + + boolean isEnd; + T65_208_Trie_2[] children; + + public T65_208_Trie_2() { + children = new T65_208_Trie_2[26]; + isEnd = false; + } + + public void insert(String word) { + T65_208_Trie_2 cur = this; + for (int i = 0; i < word.length(); i++) { + char c = word.charAt(i); + if (cur.children[c - 'a'] == null) { + cur.children[c - 'a'] = new T65_208_Trie_2(); + } + cur = cur.children[c - 'a']; + } + cur.isEnd = true;//最优一个是终点 + } + + public boolean search(String word) { + T65_208_Trie_2 node = searchPredix(word); + return node != null && node.isEnd; + } + + public boolean startsWith(String prefix) { + return searchPredix(prefix) != null; + } + + public T65_208_Trie_2 searchPredix(String word) { + T65_208_Trie_2 cur = this; + for (int i = 0; i < word.length(); i++) { + char c = word.charAt(i); + if (cur.children[c - 'a'] == null) { + return null;//没有 + } + cur = cur.children[c - 'a']; + } + return cur;//最优一个是终点 + } +} diff --git a/Leecode/src/main/java/com/markilue/leecode/hot100/second/T81_312_MaxCoins.java b/Leecode/src/main/java/com/markilue/leecode/hot100/second/T81_312_MaxCoins.java index 2cd9177..638873e 100644 --- a/Leecode/src/main/java/com/markilue/leecode/hot100/second/T81_312_MaxCoins.java +++ b/Leecode/src/main/java/com/markilue/leecode/hot100/second/T81_312_MaxCoins.java @@ -16,8 +16,8 @@ public class T81_312_MaxCoins { @Test public void test() { - int[] nums ={3,1,5,8}; - System.out.println(maxCoins(nums)); + int[] nums = {3, 1, 5, 8}; + System.out.println(maxCoins1(nums)); } @@ -62,4 +62,33 @@ public class T81_312_MaxCoins { } return memo[left][right]; } + + + //由于戳气球会导致区间变成零散，所以可以考虑变成填气球；或者可以理解为一个区间最后一次戳的气球 + public int maxCoins1(int[] nums) { + int n = nums.length; + int[] numNums = new int[n + 2]; + for (int i = 1; i < n + 1; i++) { + numNums[i] = nums[i - 1]; + } + numNums[0] = numNums[n + 1] = 1; + int[][] dp = new int[n + 2][n + 2];//dp[i][j]表示区间[i,j]的最大硬币数 + for (int i = n - 1; i >= 0; i--) { + for (int j = i + 2; j <= n + 1; j++) {//区间至少大于3才能戳 + for (int k = i + 1; k < j; k++) { + //在左区间i和右区间j中间戳 + int sum = numNums[i] * numNums[k] * numNums[j]; + //加上左区间的和右区间的 + sum += dp[i][k] + dp[k][j]; + dp[i][j] = Math.max(dp[i][j], sum); + } + } + } + + return dp[0][n + 1]; + + + } + + } diff --git a/Leecode/src/main/java/com/markilue/leecode/hot100/second/T86_394_DecodeString.java b/Leecode/src/main/java/com/markilue/leecode/hot100/second/T86_394_DecodeString.java index 64f5f29..452f457 100644 --- a/Leecode/src/main/java/com/markilue/leecode/hot100/second/T86_394_DecodeString.java +++ b/Leecode/src/main/java/com/markilue/leecode/hot100/second/T86_394_DecodeString.java @@ -22,7 +22,8 @@ public class T86_394_DecodeString { return sub(s); } - int start=0; + int start = 0; + public String sub(String s) { if (start >= s.length() || s.charAt(start) == ']') return ""; StringBuilder result = new StringBuilder(); @@ -55,4 +56,37 @@ public class T86_394_DecodeString { } + + + public String subGet(String s) { + if (start > s.length() || s.charAt(start) == ']') return ""; + + char cur = s.charAt(start); + StringBuilder result = new StringBuilder(); + if (Character.isDigit(cur)) { + int num = getNum(s); + //左括号 + start++; + String next = subGet(s); + while (num-- > 0) { + result.append(next); + } + start++;//右括号 + }else if(Character.isLetter(cur)){ + result.append(cur); + start++;//下一个 + } + //拼接剩下的 + result.append(subGet(s)); + return result.toString(); + } + + public int getNum(String s) { + int num = 0; + while (start < s.length() && Character.isDigit(s.charAt(start))) { + num = num * 10 + s.charAt(start) - '0'; + start++; + } + return num; + } } diff --git a/Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question1.java b/Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question1.java similarity index 96% rename from Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question1.java rename to Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question1.java index 53c7d5e..8c44518 100644 --- a/Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question1.java +++ b/Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question1.java @@ -1,4 +1,4 @@ -package com.markilue.leecode.interview.huawei; +package com.markilue.leecode.interview.huawei.T0531; import org.junit.Test; diff --git a/Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question2.java b/Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question2.java similarity index 95% rename from Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question2.java rename to Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question2.java index d0816f1..07845f2 100644 --- a/Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question2.java +++ b/Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question2.java @@ -1,4 +1,4 @@ -package com.markilue.leecode.interview.huawei; +package com.markilue.leecode.interview.huawei.T0531; import org.junit.Test; diff --git a/Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question3.java b/Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question3.java similarity index 60% rename from Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question3.java rename to Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question3.java index ceacc32..3caadd7 100644 --- a/Leecode/src/main/java/com/markilue/leecode/interview/huawei/Question3.java +++ b/Leecode/src/main/java/com/markilue/leecode/interview/huawei/T0531/Question3.java @@ -1,4 +1,4 @@ -package com.markilue.leecode.interview.huawei; +package com.markilue.leecode.interview.huawei.T0531; import org.junit.Test; @@ -37,7 +37,8 @@ public class Question3 { {-1, 5, 2}, {-2, -3, 4}, }; - calculateMaxRectangleSum(2, 3, income); +// calculateMaxRectangleSum(2, 3, income); + calculate(2, 3, income); } private static void calculateMaxRectangleSum(int m, int n, int[][] matrix) { @@ -70,4 +71,37 @@ public class Question3 { } + private static void calculate(int m, int n, int[][] matrix) { + + //构造前缀和数组,计算前缀和 + int[][] prefix = new int[m + 1][n + 1]; + + for (int i = 1; i < prefix.length; i++) { + for (int j = 1; j < prefix[0].length; j++) { + prefix[i][j] = prefix[i - 1][j] + prefix[i][j - 1] - prefix[i - 1][j - 1] + matrix[i - 1][j - 1]; + } + } + int result = Integer.MIN_VALUE; + int edge = 0; + //利用前缀和来判断那个矩形最大 + for (int i = 1; i < m + 1; i++) { + for (int j = 1; j < n + 1; j++) { + //左上角 + for (int k = i; k < m + 1; k++) { + for (int l = j; l < n + 1; l++) { + //右下角 + int cur = prefix[k][l] - prefix[i - 1][l] - prefix[k][j - 1] + prefix[i - 1][j - 1]; + if (result < cur) { + result = cur; + edge = (k - i + 1) * (l - j + 1); + } + } + } + } + } + System.out.println(edge + " " + result); + + + } + }