forked from sunstick/code-street
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathnext_permutation.cpp
More file actions
38 lines (30 loc) · 1.06 KB
/
next_permutation.cpp
File metadata and controls
38 lines (30 loc) · 1.06 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
/*
Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.
If such arrangement is not possible, it must rearrange it as the lowest possible order (ie, sorted in ascending order).
The replacement must be in-place, do not allocate extra memory.
Here are some examples. Inputs are in the left-hand column and its corresponding outputs are in the right-hand column.
1,2,3 → 1,3,2
3,2,1 → 1,2,3
1,1,5 → 1,5,1
*/
class Solution {
public:
void nextPermutation(vector<int> &num) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
int i = num.size() - 1;
while (i > 0 && num[i] <= num[i - 1]) i--;
if (i == 0) {
reverse(num.begin(), num.end());
return ;
}
int pivot = num[i - 1];
for (int j = num.size() - 1; j >= i; j--) {
if (num[j] > pivot) {
swap(num[i - 1], num[j]);
break;
}
}
reverse(num.begin() + i, num.end());
}
};