From 0dad9a5f7cd13b68b9a727983490bea2a5eaa992 Mon Sep 17 00:00:00 2001
From: zhicheng lee <904688436@qq.com>
Date: Tue, 13 Sep 2022 22:21:15 +0800
Subject: [PATCH] =?UTF-8?q?=E6=9B=B4=E6=96=B0=200139.=E5=8D=95=E8=AF=8D?=
 =?UTF-8?q?=E6=8B=86=E5=88=86.md=20Java=E4=BB=A3=E7=A0=81?=
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使用Set容器加速两层for循环中的查询函数，原代码在List列表中查询，本质上为三层循环，使用Set容器后为两层循环
---
 problems/0139.单词拆分.md | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/problems/0139.单词拆分.md b/problems/0139.单词拆分.md
index 7ff13f72..5b38a7a5 100644
--- a/problems/0139.单词拆分.md
+++ b/problems/0139.单词拆分.md
@@ -234,11 +234,13 @@ Java：
 ```java
 class Solution {
     public boolean wordBreak(String s, List<String> wordDict) {
+        HashSet<String> set = new HashSet<>(wordDict);
         boolean[] valid = new boolean[s.length() + 1];
         valid[0] = true;
+
         for (int i = 1; i <= s.length(); i++) {
-            for (int j = 0; j < i; j++) {
-                if (wordDict.contains(s.substring(j,i)) && valid[j]) {
+            for (int j = 0; j < i && !valid[i]; j++) {
+                if (set.contains(s.substring(j, i)) && valid[j]) {
                     valid[i] = true;
                 }
             }