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https://github.com/youngyangyang04/leetcode-master.git
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Merge branch 'youngyangyang04:master' into master
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@ -345,6 +345,79 @@ class Solution {
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}
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```
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```java
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/* 该方法是对第二个方法的改进,主要变化在于将某点的所有终点变更为链表的形式,优点在于
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1.添加终点时直接在对应位置添加节点,避免了TreeMap增元素时的频繁调整
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2.同时每次对终点进行增加删除查找时直接通过下标操作,避免hashMap反复计算hash*/
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class Solution {
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//key为起点,value是有序的终点的列表
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Map<String, LinkedList<String>> ticketMap = new HashMap<>();
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LinkedList<String> result = new LinkedList<>();
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int total;
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public List<String> findItinerary(List<List<String>> tickets) {
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total = tickets.size() + 1;
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//遍历tickets,存入ticketMap中
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for (List<String> ticket : tickets) {
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addNew(ticket.get(0), ticket.get(1));
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}
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deal("JFK");
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return result;
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}
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boolean deal(String currentLocation) {
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result.add(currentLocation);
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//机票全部用完,找到最小字符路径
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if (result.size() == total) {
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return true;
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}
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//当前位置的终点列表
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LinkedList<String> targetLocations = ticketMap.get(currentLocation);
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//没有从当前位置出发的机票了,说明这条路走不通
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if (targetLocations != null && !targetLocations.isEmpty()) {
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//终点列表中遍历到的终点
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String targetLocation;
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//遍历从当前位置出发的机票
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for (int i = 0; i < targetLocations.size(); i++) {
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targetLocation = targetLocations.get(i);
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//删除终点列表中当前的终点
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targetLocations.remove(i);
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//递归
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if (deal(targetLocation)) {
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return true;
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}
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//路线走不通,将机票重新加回去
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targetLocations.add(i, targetLocation);
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result.removeLast();
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}
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}
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return false;
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}
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/**
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* 在map中按照字典顺序添加新元素
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*
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* @param start 起点
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* @param end 终点
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*/
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void addNew(String start, String end) {
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LinkedList<String> startAllEnd = ticketMap.getOrDefault(start, new LinkedList<>());
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if (!startAllEnd.isEmpty()) {
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for (int i = 0; i < startAllEnd.size(); i++) {
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if (end.compareTo(startAllEnd.get(i)) < 0) {
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startAllEnd.add(i, end);
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return;
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}
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}
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startAllEnd.add(startAllEnd.size(), end);
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} else {
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startAllEnd.add(end);
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ticketMap.put(start, startAllEnd);
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}
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}
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}
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```
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### Python
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回溯 使用used数组
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@ -396,25 +396,33 @@ function nextGreaterElement(nums1: number[], nums2: number[]): number[] {
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### Rust
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```rust
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use std::collections::HashMap;
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impl Solution {
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pub fn next_greater_element(nums1: Vec<i32>, nums2: Vec<i32>) -> Vec<i32> {
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let mut ans = vec![-1; nums1.len()];
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use std::collections::HashMap;
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let mut map = HashMap::new();
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for (idx, &i) in nums1.iter().enumerate() {
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map.insert(i, idx);
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let (mut res, mut map) = (vec![-1; nums1.len()], HashMap::new());
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if nums1.is_empty() {
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return res;
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}
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nums1.into_iter().enumerate().for_each(|(v, k)| {
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map.insert(k, v);
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});
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let mut stack = vec![];
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for (idx, &i) in nums2.iter().enumerate() {
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while !stack.is_empty() && nums2[*stack.last().unwrap()] < i {
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let pos = stack.pop().unwrap();
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if let Some(&jdx) = map.get(&nums2[pos]) {
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ans[jdx] = i;
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for (i, &value) in nums2.iter().enumerate() {
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while let Some(&top) = stack.last() {
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if value <= nums2[top] {
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break;
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}
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let stacked_index = stack.pop().unwrap();
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if let Some(&mapped_index) = map.get(&nums2[stacked_index]) {
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res[mapped_index] = value;
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}
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}
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stack.push(idx);
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stack.push(i);
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}
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ans
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res
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}
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}
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```
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@ -293,6 +293,28 @@ impl Solution {
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}
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```
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> 版本二:
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```rust
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impl Solution {
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pub fn next_greater_elements(nums: Vec<i32>) -> Vec<i32> {
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let (mut stack, mut res) = (vec![], vec![-1; nums.len()]);
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for i in 0..nums.len() * 2 {
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while let Some(&top) = stack.last() {
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if nums[i % nums.len()] <= nums[top] {
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break;
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}
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let saved_index = stack.pop().unwrap();
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res[saved_index] = nums[i % nums.len()];
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}
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stack.push(i % nums.len());
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}
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res
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}
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}
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```
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<p align="center">
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<a href="https://programmercarl.com/other/kstar.html" target="_blank">
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