EI judge 002 Set Intersection 算法题解

EI judge 002 Set Intersection 算法题解2015-02-25

Set Intersection

Time limit = 5 second（s）

Memory limit = 33000 Kb

Your task is to find the intersection of two sets of positive integers.

Input The input consists of two sets of positive integers A={a₁, a₂, ..., a_n} and B={b₁, b₂, ..., b_k} represented as two whitespace-separated lists of numbers. Each list ends with -1, that serves as an end-of-set marker. Repetitions of elements are possible in the input, but not in the output. You may assume that 0 < a_i, b_i < 10⁶ and that the sets A and B are of size less than 1000.

Output is list of numbers or word "empty" if intersection is empty.

注意地方：

1 防止重复 -- 这里使用set，第二次遍历数组的时候，记得把set重的数据erase掉

2 输出格式这个oj也很严格的，不能多一个空格

#include <iostream>#include <string>#include <vector>#include <algorithm>#include <set>using namespace std;int A[1000] = {0};void SetIntersection（）{set<int> si;int a = 0;while （cin>>a && -1 ！= a）{si.insert（a）;}int j = 0;while （cin>>a && -1 ！= a）{if （si.count（a））{A[j++] = a;si.erase（a）;}}if （！j） cout<<"empty";else{j--;for （int i = 0; i < j; i++）{cout<<A[i]<<" ";}cout<<A[j];//原来要防止多输出一个" "}}

From：csdn博客靖心