Repository navigation
Expand file tree
/
Copy pathalgorithm.cpp
More file actions
220 lines (195 loc) · 5.67 KB
/
Copy pathalgorithm.cpp
File metadata and controls
220 lines (195 loc) · 5.67 KB
1
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
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
#include "common.hpp"
int main() {
{
assert(std::min(0.1, 0.2) == 0.1);
assert(std::max(0.1, 0.2) == 0.2);
}
// # sort
{
std::vector<int> v{2, 0, 1};
std::sort(v.begin(), v.end());
std::vector<int> v1 = {0, 1, 2};
assert((v == std::vector<int>{0, 1, 2}));
}
// # reverse
{
std::vector<int> v{2, 0, 1};
std::reverse(v.begin(), v.end());
assert((v == std::vector<int>{1, 0, 2}));
}
/* # swap
*
* Does things equivalent to:
*
* template <class T> void swap (T& a, T& b)
* {
* T c(a); a=b; b=c;
* }
*
* However stdlib can specialize it to do operations more efficiently.
*
* Some stdlib classes implement swap as a method.
*
* Particularly important because of the copy and swap idiom.
*/
// # randomize
{
std::vector<int> v{2, 0, 1};
std::random_shuffle(v.begin(), v.end());
}
// # copy
{
std::vector<int> v{2, 0, 1};
std::vector<int> v2(5, 3);
std::copy(v.begin(), v.end(), v2.begin() + 1);
assert(v2 == std::vector<int>({3, 2, 0, 1, 3}));
}
/* # equal
*
* Compares ranges of two containers.
*/
{
std::vector<int> v {0, 1, 2 };
std::vector<int> v2{ 1, 2, 3};
assert(std::equal(v.begin() + 1, v.end(), v2.begin()));
}
/* # accumulate
*
* Sum over range with operator+
*
* Also has functional versions http://www.cplusplus.com/reference/numeric/accumulate/
*/
{
{
std::vector<int> v{2, 0, 1};
assert(std::accumulate(v.begin(), v.end(), 0) == 3);
assert(std::accumulate(v.begin(), v.end(), 10) == 13);
}
// The functional version can be used to add up arrays.
// http://stackoverflow.com/questions/26941943/how-to-add-all-numbers-in-an-array-c
{
int a[] = {1, 3, 5, 7, 9};
assert(std::accumulate(std::begin(a), std::end(a), 0, std::plus<int>()) == 25);
}
}
/* # find
*
* Return iterator to first found element.
*/
{
std::vector<int> v{2,0,1};
unsigned int pos;
pos = std::find(v.begin(), v.end(), 0) - v.begin();
assert(pos == 1);
pos = std::find(v.begin(), v.end(), 1) - v.begin();
assert(pos == 2);
pos = std::find(v.begin(), v.end(), 2) - v.begin();
assert(pos == 0);
pos = std::find(v.begin(), v.end(), 3) - v.begin(); //end() returned
assert(pos == v.size());
}
/* # find_if
*
* Like find, but using an arbitrary condition on each element instead of equality.
*
* Consider usage with C++11 lambdas and functional.
*/
{
std::vector<int> v{2, 0, 1};
assert(std::find_if (v.begin(), v.end(), odd) == --v.end());
}
/* # binary_search
*
* Container must be already sorted.
*
* Log complexity.
*
* Only states if the element is present or not, but does not get its position.
*
* If you want to get the position of those items, use `equal_range`, `lower_bound` or `upper_bound`.
*/
{
std::vector<int> v{0, 1, 2};
assert(std::binary_search(v.begin(), v.end(), 1) == true);
assert(std::binary_search(v.begin(), v.end(), 3) == false);
assert(std::binary_search(v.begin(), v.end() - 1, 2) == false);
}
/* # lower_bound
*
* Finds first element in container which is not less than val.
*/
{
std::vector<int> v{0, 2, 3};
auto it = std::lower_bound(v.begin(), v.end(), 1);
assert(it - v.begin() == 1);
}
/* # upper_bound
*
* Finds first element in container is greater than val.
*/
{
std::vector<int> v{0, 1, 2};
auto it = std::upper_bound(v.begin(), v.end(), 1);
assert(it - v.begin() == 2);
}
/* # equal_range
*
* Finds first and last location of a value iniside a ranged container.
*
* Return values are the same as lower_bound and upper_bound.
*
* log complexity.
*/
{
std::vector<int> v{0, 1, 1, 2};
std::vector<int>::iterator begin, end;
std::tie(begin, end) = std::equal_range(v.begin(), v.end(), 1);
assert(begin - v.begin() == 1);
assert(end - v.begin() == 3);
}
// # count
{
std::vector<int> v{2,1,2};
assert(std::count(v.begin(), v.end(), 0) == 0);
assert(std::count(v.begin(), v.end(), 1) == 1);
assert(std::count(v.begin(), v.end(), 2) == 2);
}
// # max_element #min_element
{
std::vector<int> v{2,0,1};
assert(*std::max_element(v.begin(), v.end()) == 2);
assert(*std::min_element(v.begin(), v.end()) == 0);
}
/* # advance
*
* Advance iterator by given number.
*
* If random access, simply adds + N.
*
* Else, calls `++` N times.
*
* Advantage over `+`: only random access containers support `+`,
* but this works for any container, allowing one to write more general code.
*
* Beware however that this operation will be slow for non random access containers.
*/
{
std::vector<int> v{0, 1, 2};
auto it = v.begin();
std::advance(it, 2);
assert(*it == 2);
}
#if __cplusplus >= 201103L
/* # next
*
* Same as advance, but returns a new iterator instead of modifying the old one.
*/
{
std::vector<int> v{0, 1, 2};
auto it(v.begin());
auto itNext = std::next(it, 2);
assert(*it == 0);
assert(*itNext == 2);
}
#endif
}