常用算法讲解

最短路径：Dijkstra 算法

https://leetcode-cn.com/problems/network-delay-time/solution/by-nehzil-d1b8/

最短路径

https://leetcode-cn.com/problems/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance/solution/zui-duan-lu-jing-mo-ban-da-ji-he-cban-fl-gs7u/

https://leetcode.cn/problems/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance/solution/zui-duan-lu-jing-mo-ban-da-ji-he-cban-fl-gs7u/

并查集关键函数

    int find(int x, vector<int>& parent) {
        if (parent[x] == x) {
            return x;
        }
        parent[x] = find(parent[x], parent);
        return parent[x];
    }
    void Merge(int x, int y, vector<int>& parent) {
        parent[find(x, parent)] = find(y, parent);
    }

 贪心算法：

https://leetcode.cn/problems/non-overlapping-intervals/solution/wu-zhong-die-qu-jian-by-leetcode-solutio-cpsb/

https://leetcode.cn/problems/minimum-number-of-arrows-to-burst-balloons/solution/yong-zui-shao-shu-liang-de-jian-yin-bao-qi-qiu-1-2/

双指针，单调栈

https://leetcode.cn/problems/trapping-rain-water/solution/jie-yu-shui-by-leetcode-solution-tuvc/