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Merged
GeekUniversity merged 1 commit into from
May 13, 2019
Merged

074-week4 第四周作业 #678

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66 changes: 66 additions & 0 deletions Week_04/id_74/LeetCode_211_74.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,66 @@
class WordDictionary {
public class TrieNode {
public char data;
public TrieNode[] children = new TrieNode[26];
public boolean isEndingChar = false;
public TrieNode(char data) {
this.data = data;
}
}

private TrieNode root;

/** Initialize your data structure here. */
public WordDictionary() {
root = new TrieNode('/');
}

/** Adds a word into the data structure. */
public void addWord(String word) {
TrieNode n = root;
for (char c : word.toCharArray()) {
int index = c - 'a';
if (n.children[index] == null) {
n.children[index] = new TrieNode(c);
}
n = n.children[index];
}
n.isEndingChar = true;
}

/** Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter. */
public boolean search(String word) {
return match(word, 0, root);
}

private boolean match(String word, int start, TrieNode node) {
if (start == word.length()) {
return node.isEndingChar;
}

char c = word.charAt(start);
if (c == '.') {
for (TrieNode n : node.children) {
if (n != null) {
if (match(word, start + 1, n)) {
return true;
}
}
}
} else {
if (node.children[c - 'a'] == null) {
return false;
}
return match(word, start + 1, node.children[c - 'a']);
}

return false;
}
}

/**
* Your WordDictionary object will be instantiated and called as such:
* WordDictionary obj = new WordDictionary();
* obj.addWord(word);
* boolean param_2 = obj.search(word);
*/
32 changes: 32 additions & 0 deletions Week_04/id_74/LeetCode_241_74.java
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import java.util.*;

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@tidelgl tidelgl May 11, 2019

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注释有点少，想学一下解题思路

class Solution {
public List<Integer> diffWaysToCompute(String input) {
List<Integer> result = new ArrayList<>();
for (int i = 0; i < input.length(); i++) {
char op = input.charAt(i);
if (op == '-' || op == '*' || op == '+') {
String p1 = input.substring(0, i);
String p2 = input.substring(i+1);
List<Integer> result1 = diffWaysToCompute(p1);
List<Integer> result2 = diffWaysToCompute(p2);

for (Integer r1 : result1) {
for (Integer r2 : result2) {
if (op == '+') {
result.add(r1 + r2);
} else if (op == '-') {
result.add(r1 - r2);
} else if (op == '*') {
result.add(r1 * r2);
}
}
}
}
}
if (result.size() == 0) {
result.add(Integer.valueOf(input));
}
return result;
}
}