网站建设培训 苏州,企业做网站的费用怎么入账,和谐校园网站建设,163k地方门户网站系统algorithm此头文件是算法库的一部分。本篇介绍划分操作和排序操作。 划分操作 is_partitioned (C11) 判断范围是否已按给定的谓词划分 (函数模板) partition 将范围中的元素分为两组 (函数模板) partition_copy (C11) 复制一个范围#xff0c;将各元素分为两组 (函数模板) st…algorithm此头文件是算法库的一部分。本篇介绍划分操作和排序操作。 划分操作 is_partitioned (C11) 判断范围是否已按给定的谓词划分 (函数模板) partition 将范围中的元素分为两组 (函数模板) partition_copy (C11) 复制一个范围将各元素分为两组 (函数模板) stable_partition 将元素分为两组同时保留其相对顺序 (函数模板) partition_point (C11) 定位已划分范围的划分点 (函数模板) 排序操作 is_sorted (C11) 检查范围是否已按升序排列 (函数模板) is_sorted_until (C11) 找出最大的有序子范围 (函数模板) sort 将范围按升序排序 (函数模板) partial_sort 排序一个范围的前 N 个元素 (函数模板) partial_sort_copy 对范围内的元素进行复制并部分排序 (函数模板) stable_sort 将范围内的元素排序同时保持相等的元素之间的顺序 (函数模板) nth_element 将给定的范围部分排序确保其按给定元素划分
示例代码
#include algorithm
#include functional
#include iostream
#include iterator
#include utility // std::pair
#include vector
#include array
#include cctype // std::tolower
#include string
#include ctime // std::time
#include cstdlib // std::rand, std::srand
#include random // std::default_random_engine
#include chrono // std::chrono::system_clockbool IsOdd5(int i) { return ((i % 2) 1); }bool myfunction7(int i, int j) { return (i j); }struct myclass10{bool operator() (int i, int j) { return (i j); }
} myobject10;bool compare_as_ints(double i, double j)
{return (int(i) int(j));
}int main()
{// is_partitioned algorithm examplestd::arrayint, 7 foo{ 1,2,3,4,5,6,7 };// print contents:std::cout foo:; for (int x : foo) std::cout x;if (std::is_partitioned(foo.begin(), foo.end(), IsOdd5))std::cout (partitioned)\n;elsestd::cout (not partitioned)\n;// partition array:std::partition(foo.begin(), foo.end(), IsOdd5);// print contents again:std::cout foo:; for (int x : foo) std::cout x;if (std::is_partitioned(foo.begin(), foo.end(), IsOdd5))std::cout (partitioned)\n;elsestd::cout (not partitioned)\n;// partition algorithm examplestd::vectorint myvector;// set some values:for (int i 1; i 10; i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9std::vectorint::iterator bound;bound std::partition(myvector.begin(), myvector.end(), IsOdd5);// print out content:std::cout odd elements:;for (std::vectorint::iterator it myvector.begin(); it ! bound; it)std::cout *it;std::cout \n;std::cout even elements:;for (std::vectorint::iterator it bound; it ! myvector.end(); it)std::cout *it;std::cout \n;// stable_partition examplestd::vectorint myvector2;// set some values:for (int i 1; i 10; i) myvector2.push_back(i); // 1 2 3 4 5 6 7 8 9std::vectorint::iterator bound2;bound2 std::stable_partition(myvector2.begin(), myvector2.end(), IsOdd5);// print out content:std::cout odd elements:;for (std::vectorint::iterator it myvector2.begin(); it ! bound2; it)std::cout *it;std::cout \n;std::cout even elements:;for (std::vectorint::iterator it bound2; it ! myvector2.end(); it)std::cout *it;std::cout \n;// partition_copy examplestd::vectorint foo2{ 1,2,3,4,5,6,7,8,9 };std::vectorint odd2, even2;// resize vectors to proper size:unsigned n std::count_if(foo2.begin(), foo2.end(), IsOdd5);odd2.resize(n); even2.resize(foo2.size() - n);// partition:std::partition_copy(foo2.begin(), foo2.end(), odd2.begin(), even2.begin(), IsOdd5);// print contents:std::cout odd2: ; for (int x : odd2) std::cout x; std::cout \n;std::cout even2: ; for (int x : even2) std::cout x; std::cout \n;// partition_point examplestd::vectorint foo3{ 1,2,3,4,5,6,7,8,9 };std::vectorint odd3;std::partition(foo3.begin(), foo3.end(), IsOdd5);auto it std::partition_point(foo3.begin(), foo3.end(), IsOdd5);odd3.assign(foo3.begin(), it);// print contents of odd3:std::cout odd3:;for (int x : odd3) std::cout x;std::cout \n;// sort algorithm exampleint myints4[] { 32,71,12,45,26,80,53,33 };std::vectorint myvector4(myints4, myints4 8); // 32 71 12 45 26 80 53 33// using default comparison (operator ):std::sort(myvector4.begin(), myvector4.begin() 4); //(12 32 45 71)26 80 53 33// using function as compstd::sort(myvector4.begin() 4, myvector4.end(), myfunction7); // 12 32 45 71(26 33 53 80)// using object as compstd::sort(myvector4.begin(), myvector4.end(), myobject10); //(12 26 32 33 45 53 71 80)// print out content:std::cout myvector4 contains:;for (std::vectorint::iterator it myvector4.begin(); it ! myvector4.end(); it)std::cout *it;std::cout \n;// stable_sort exampledouble mydoubles[] { 3.14, 1.41, 2.72, 4.67, 1.73, 1.32, 1.62, 2.58 };std::vectordouble myvector5;myvector5.assign(mydoubles, mydoubles 8);std::cout using default comparison:;std::stable_sort(myvector5.begin(), myvector5.end());for (std::vectordouble::iterator it myvector5.begin(); it ! myvector5.end(); it)std::cout *it;std::cout \n;myvector5.assign(mydoubles, mydoubles 8);std::cout using compare_as_ints :;std::stable_sort(myvector5.begin(), myvector5.end(), compare_as_ints);for (std::vectordouble::iterator it myvector5.begin(); it ! myvector5.end(); it)std::cout *it;std::cout \n;// partial_sort exampleint myints6[] { 9,8,7,6,5,4,3,2,1 };std::vectorint myvector6(myints6, myints6 9);// using default comparison (operator ):std::partial_sort(myvector6.begin(), myvector6.begin() 5, myvector6.end());// using function as compstd::partial_sort(myvector6.begin(), myvector6.begin() 5, myvector6.end(), myfunction7);// print out content:std::cout myvector6 contains:;for (std::vectorint::iterator it myvector6.begin(); it ! myvector6.end(); it)std::cout *it;std::cout \n;// partial_sort_copy exampleint myints7[] { 9,8,7,6,5,4,3,2,1 };std::vectorint myvector7(5);// using default comparison (operator ):std::partial_sort_copy(myints7, myints7 9, myvector7.begin(), myvector7.end());// using function as compstd::partial_sort_copy(myints7, myints7 9, myvector7.begin(), myvector7.end(), myfunction7);// print out content:std::cout myvector7 contains:;for (std::vectorint::iterator it myvector7.begin(); it ! myvector7.end(); it)std::cout *it;std::cout \n;// is_sorted examplestd::arrayint, 4 foo4{ 2,4,1,3 };do {// try a new permutation:std::prev_permutation(foo4.begin(), foo4.end());// print range:std::cout foo4:;for (int x : foo4) std::cout x;std::cout \n;} while (!std::is_sorted(foo4.begin(), foo4.end()));std::cout the range is sorted!\n;// is_sorted_until examplestd::arrayint, 4 foo5{ 2,4,1,3 };std::arrayint, 4::iterator it5;do {// try a new permutation:std::prev_permutation(foo5.begin(), foo5.end());// print range:std::cout foo5:;for (int x : foo5) std::cout x;it5 std::is_sorted_until(foo5.begin(), foo5.end());std::cout ( (it5 - foo5.begin()) elements sorted)\n;} while (it5 ! foo5.end());std::cout the range is sorted!\n;// nth_element examplestd::vectorint myvector8;// set some values:for (int i 1; i 10; i) myvector8.push_back(i); // 1 2 3 4 5 6 7 8 9std::random_shuffle(myvector8.begin(), myvector8.end());// using default comparison (operator ):std::nth_element(myvector8.begin(), myvector8.begin() 5, myvector8.end());// using function as compstd::nth_element(myvector8.begin(), myvector8.begin() 5, myvector8.end(), myfunction7);// print out content:std::cout myvector8 contains:;for (std::vectorint::iterator it myvector8.begin(); it ! myvector8.end(); it)std::cout *it;std::cout \n;return 0;
}
运行结果 参考
https://cplusplus.com/reference/algorithm/
标准库标头 algorithm - cppreference.com
