51 lines
1.4 KiB
Markdown
51 lines
1.4 KiB
Markdown
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* [点击阅读面试进阶指南 ](https://github.com/CyC2018/Backend-Interview-Guide)
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<!-- GFM-TOC -->
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* [给表达式加括号](#给表达式加括号)
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<!-- GFM-TOC -->
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# 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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