1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <algorithm> 11 12 // template<RandomAccessIterator Iter> 13 // requires ShuffleIterator<Iter> 14 // && LessThanComparable<Iter::value_type> 15 // void 16 // nth_element(Iter first, Iter nth, Iter last); 17 18 #include <algorithm> 19 #include <cassert> 20 21 void 22 test_one(unsigned N, unsigned M) 23 { 24 assert(N != 0); 25 assert(M < N); 26 int* array = new int[N]; 27 for (int i = 0; i < N; ++i) 28 array[i] = i; 29 std::random_shuffle(array, array+N); 30 std::nth_element(array, array+M, array+N); 31 assert(array[M] == M); 32 std::nth_element(array, array+N, array+N); // begin, end, end 33 delete [] array; 34 } 35 36 void 37 test(unsigned N) 38 { 39 test_one(N, 0); 40 test_one(N, 1); 41 test_one(N, 2); 42 test_one(N, 3); 43 test_one(N, N/2-1); 44 test_one(N, N/2); 45 test_one(N, N/2+1); 46 test_one(N, N-3); 47 test_one(N, N-2); 48 test_one(N, N-1); 49 } 50 51 int main() 52 { 53 int d = 0; 54 std::nth_element(&d, &d, &d); 55 assert(d == 0); 56 test(256); 57 test(257); 58 test(499); 59 test(500); 60 test(997); 61 test(1000); 62 test(1009); 63 } 64
