摘要： 前中后序的相互转换只需要考虑对应的子树是否存在节点即可，有中序的顺序判断子树关系，由前（开始为根）或后（末尾为根）序遍历判断当前子树的根是哪个节点； 阅读全文

摘要： Recommendation system predicts the preference that a user would give to an item. Now you are asked to program a very simple recommendation system that 阅读全文

摘要： In the big cities, the subway systems always look so complex to the visitors. To give you some sense, the following figure shows the map of Beijing su 阅读全文

摘要： #include<iostream> #include<sstream>#include<string>using namespace std;int n;bool judge(string s){ long long t1, t2, t3; stringstream ss; /*ss.clear( 阅读全文

摘要： #include <iostream>#include <vector>using namespace std;int main() { int n, m, k, nv, a, b, num; scanf("%d%d", &n, &m); vector<int> v[n]; for (int i = 阅读全文

摘要： #include<iostream>#include<string>#include<algorithm>using namespace std;string rev(string s){ reverse(s.begin(), s.end()); return s;}string add(strin 阅读全文

摘要： After each PAT, the PAT Center will announce the ranking of institutions based on their students’ performances. Now you are asked to generate the rank 阅读全文

摘要： #include<iostream> #include<stdio.h> #include<vector> #include<algorithm> #include<time.h> #include<set> #pragma warning(disable:4996) using namespace std; struct coordinate { int x, y; }; bool cmp_x( 阅读全文

摘要： This is a problem given in the Graduate Entrance Exam in 2018: Which of the following is NOT a topological order obtained from the given directed grap 阅读全文

摘要： The lowest common ancestor (LCA) of two nodes U and V in a tree is the deepest node that has both U and V as descendants. Given any two nodes in a bin 阅读全文