binary_search
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判断范围中是否存在值等价于给定值的元素 |
equal_range
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返回范围中值等于给定值的元素组成的子范围 |
lower_bound
|
返回指向范围中第一个值大于或等于给定值的元素的迭代器 |
upper_bound
|
返回指向范围中第一个值大于给定值的元素的迭代器 |
binary_search
?判断范围中是否存在值等价于给定值的元素
|
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 |
// binary_search example
#include <iostream> // std::cout #include <algorithm> // std::binary_search, std::sort #include <vector> // std::vector bool myfunction (int i,int j) { return (i<j); } int main () { int myints[] = {1,2,3,4,5,4,3,2,1}; std::vector<int> v(myints,myints+9); // 1 2 3 4 5 4 3 2 1 // using default comparison: std::sort (v.begin(), v.end()); std::cout << "looking for a 3... "; if (std::binary_search (v.begin(), v.end(), 3)) std::cout << "found!\n"; else std::cout << "not found.\n"; // using myfunction as comp: std::sort (v.begin(), v.end(), myfunction); std::cout << "looking for a 6... "; if (std::binary_search (v.begin(), v.end(), 6, myfunction)) std::cout << "found!\n"; else std::cout << "not found.\n"; return 0; } |
输出：
|
2 |
looking for a 3... found!
looking for a 6... not found. |
equal_range
返回范围中值等于给定值的元素组成的子范围
|
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 |
// equal_range example
#include <iostream> // std::cout #include <algorithm> // std::equal_range, std::sort #include <vector> // std::vector bool mygreater (int i,int j) { return (i>j); } int main () { int myints[] = {10,20,30,30,20,10,10,20}; std::vector<int> v(myints,myints+8); // 10 20 30 30 20 10 10 20 std::pair<std::vector<int>::iterator,std::vector<int>::iterator> bounds; // using default comparison: std::sort (v.begin(), v.end()); // 10 10 10 20 20 20 30 30 bounds=std::equal_range (v.begin(), v.end(), 20); // ^ ^ // using "mygreater" as comp: std::sort (v.begin(), v.end(), mygreater); // 30 30 20 20 20 10 10 10 bounds=std::equal_range (v.begin(), v.end(), 20, mygreater); // ^ ^ std::cout << "bounds at positions " << (bounds.first - v.begin()); std::cout << " and " << (bounds.second - v.begin()) << ‘\n‘; return 0; } |
输出：
|
|
bounds at positions 2 and 5
|
lower_bound
返回指向范围中第一个值大于或等于给定值的元素的迭代器
upper_bound
返回指向范围中第一个值大于给定值的元素的迭代器
|
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 |
// lower_bound/upper_bound example
#include <iostream> // std::cout #include <algorithm> // std::lower_bound, std::upper_bound, std::sort #include <vector> // std::vector int main () { int myints[] = {10,20,30,30,20,10,10,20}; std::vector<int> v(myints,myints+8); // 10 20 30 30 20 10 10 20 std::sort (v.begin(), v.end()); // 10 10 10 20 20 20 30 30 std::vector<int>::iterator low,up; low=std::lower_bound (v.begin(), v.end(), 20); // ^ up= std::upper_bound (v.begin(), v.end(), 20); // ^ std::cout << "lower_bound at position " << (low- v.begin()) << ‘\n‘; std::cout << "upper_bound at position " << (up - v.begin()) << ‘\n‘; return 0; } |
输出：
|
2 |
lower_bound at position 3
upper_bound at position 6 |