56 lines
1.6 KiB
Markdown
56 lines
1.6 KiB
Markdown
<!-- GFM-TOC -->
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* [1. 给表达式加括号](#1-给表达式加括号)
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<!-- GFM-TOC -->
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# 1. 给表达式加括号
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[241. Different Ways to Add Parentheses (Medium)](https://leetcode.com/problems/different-ways-to-add-parentheses/description/)
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```html
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Input: "2-1-1".
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((2-1)-1) = 0
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(2-(1-1)) = 2
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Output : [0, 2]
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```
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```java
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public List<Integer> diffWaysToCompute(String input) {
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List<Integer> ways = new ArrayList<>();
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for (int i = 0; i < input.length(); i++) {
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char c = input.charAt(i);
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if (c == '+' || c == '-' || c == '*') {
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List<Integer> left = diffWaysToCompute(input.substring(0, i));
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List<Integer> right = diffWaysToCompute(input.substring(i + 1));
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for (int l : left) {
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for (int r : right) {
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switch (c) {
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case '+':
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ways.add(l + r);
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break;
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case '-':
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ways.add(l - r);
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break;
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case '*':
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ways.add(l * r);
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break;
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}
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}
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}
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}
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}
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if (ways.size() == 0) {
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ways.add(Integer.valueOf(input));
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}
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return ways;
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}
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```
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</br><div align="center">公众号 CyC2018，专注于核心基础知识分享、求职指导、技术成长。在公众号后台回复 ziliao 可领取复习大纲，帮你理清复习重点。</div></br>
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<div align="center"><img width="180px" src="https://cyc-1256109796.cos.ap-guangzhou.myqcloud.com/%E5%85%AC%E4%BC%97%E5%8F%B7.jpg"></img></div>
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