關於C++中使用set_union、set_intersection、set_difference的總結
阿新 • • 發佈:2019-02-11
STL set中有set_union(取兩集合並集)、set_intersection(取兩集合交集)、set_difference(取兩集合差集)。1、這幾個函式的引數一樣。2、set_union(x1.begin(), x1.end(), x2.begin(), x2.end(), inserter(x, x.end())),前兩個引數是集合x1的頭尾,再依次是集合x2的頭尾,最後一個引數就是將集合x1和集合x2取合集後存入集合x中。
輸出結果:/* Input: 第一行輸入一個正整數T,表示測試次數; 然後下面有2T行,每一行都有n+1個數字,其中第一個數字是n(0<=n<=100),表示該行後面還有n個數字輸入。 Output: 對於每組測試資料,首先輸出測試資料序號,”Case #.NO”, 接下來輸出共5行,每行都是一個集合, 前2行分別輸出集合A、B,接下3行來分別輸出集合A、B的並(A u B)、交(A n B)、差(A – B)。 集合中的元素用“{}”擴起來,且元素之間用“,”隔開。 Input: 1 1 2 3 1 0 Output: Case# 1: A = {1, 2, 3} B = {} A u B = {1, 2, 3} A n B = {} A - B = {1, 2, 3} */ #include<iostream> #include<set> #include<cstdio> #include<algorithm> using namespace std; int main() { set<int> x1; set<int> x2; set<int> C1; set<int> C2; set<int> C3; set<int>::iterator pos; int T,flag=0; cin >> T; while(T--) { flag++; int x1_i,x2_i,item; cin>>x1_i; for(int i = 0; i < x1_i; i++) { cin >> item; x1.insert(item); } cin >> x2_i; for(int i = 0; i < x2_i; i++) { cin >> item; x2.insert(item); } cout << "Case: " << flag <<endl; cout << "x1 = { "; for(pos = x1.begin(); pos != x1.end(); pos++) { if(pos != x1.begin()) cout << " ,"; cout << *pos; } cout << " }" << endl << "x2 = { "; for(pos = x2.begin(); pos != x2.end(); pos++) { if(pos != x2.begin()) cout << " ,"; cout << *pos; } cout<< " }" << endl << "x1 u x2 = { "; set_union(x1.begin(), x1.end(), x2.begin(), x2.end(), inserter(C1, C1.begin())); for(pos = C1.begin(); pos != C1.end(); pos++) { if(pos != C1.begin()) cout << " ,"; cout << *pos; } cout<< " }" << endl << "x1 n x2 = { "; set_intersection(x1.begin(), x1.end(), x2.begin(), x2.end(), inserter(C2, C2.begin())); for(pos = C2.begin(); pos != C2.end(); pos++) { if(pos != C2.begin()) cout << " ,"; cout << *pos; } cout<< " }" << endl << "x1 - x2 = {"; set_difference(x1.begin(), x1.end(), x2.begin(), x2.end(), inserter(C3, C3.begin())); for(pos = C3.begin(); pos != C3.end(); pos++) { if(pos != C3.begin()) cout << " ,"; cout << *pos; } cout << " }" << endl; } return 0; }