sstream ss()自动去除空格 例: string a="1 2 3 4 5; getline(cin,a); sstream ss(a); while(ss>>b) { cout<<b<<endl; } 输出是1\n2\n3\n4\n; unique的作用是“去掉”容器中相邻元素的重复元素 它实质上是一个伪去除 它会把重复的元素添加到容器末尾 而返回值是去重之后的尾地址 ]={,,,,,,,,,}; )-num;…

题目链接: https://vjudge.net/problem/POJ-1679 题目大意: 给定一个无向连通网,判断最小生成树是否唯一. 思路: (1)对图中的每条边,扫描其他边,如果存在相同权值的边,对该边做标记. (2)然后用kruskal算法或者prim算法求MST(标记MST中的边) (3)求得MST后,如果MST中未包含做了标记的边,那么MST唯一. MST中不包含未标记的边,说明MST中没有那些权值相同的边,用kruskal算法可知,该最小生成树肯定唯一. (4)如果包含标记的边…

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=2587 题意:判断最小割是否唯一. 思路: 最小割唯一性的判断是先跑一遍最大流,然后在残留网络中分别从源点和汇点出发dfs,只有当该边还有流量可用时可以访问下一个顶点,最后如果所有顶点都访问了,那么就是唯一的,否则不唯一. 接下来图解一下: 先看下面这个容量均为1的图: 跑一遍最大流后的残留网络如下(只画正向弧): 接下来从源点和汇点出发都无法访问任何顶点,因为剩余流量皆为…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 22668   Accepted: 8038 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree): Consider a connected, undire…

A. Bear and Three Balls time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Limak is a little polar bear. He has n balls, the i-th ball has size ti. Limak wants to give one ball to each of his…

[题目链接] 点击打开链接 [算法] 先求出图的最小生成树 枚举不在最小生成树上的边,若加入这条边,则形成了一个环,如果在环上且在最小生成树上的权值最大的边等于 这条边的权值,那么,显然最小生成树不唯一 树上倍增可以解决这个问题 [代码] #include <algorithm> #include <bitset> #include <cctype> #include <cerrno> #include <clocale> #include &l…

http://poj.org/problem?id=1679 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree): Consider a connected, undirected graph G = (V, E). A spanning tree of G is a subgraph of G, say…

Consider the string s to be the infinite wraparound string of "abcdefghijklmnopqrstuvwxyz", so s will look like this: "...zabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd....". Now we have another string p. Your job is to find…

A string such as "word" contains the following abbreviations: ["word", "1ord", "w1rd", "wo1d", "wor1", "2rd", "w2d", "wo2", "1o1d", "1or1", "…

Given a non-negative integer n, count all numbers with unique digits, x, where 0 ≤ x < 10n. Example: Given n = 2, return 91. (The answer should be the total numbers in the range of 0 ≤ x < 100, excluding [11,22,33,44,55,66,77,88,99]) Hint: A direct…