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// 77. Combinations
#include "leetcode.h"
/*
* given two integers 'n' and 'k', return all possible combinations of 'k'
* numbers chosen from the range '[1, n]'. you may return the answer in any
* order
*/
class Solution {
public:
vvd(int) combine(int n, int k) {
vvd(int) ans;
int i = 0;
vector<int> p(k, 0);
while (i >= 0) {
p[i]++;
if (p[i] > n)
--i;
else if (i == k - 1)
ans.push_back(p);
else
i++, p[i] = p[i - 1];
}
return ans;
}
};
int main() {
Solution obj;
for (auto i : obj.combine(4, 2))
for (auto j : i)
printf("%d ", j); // expect: [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]
printf("\n");
for (auto i : obj.combine(1, 1))
for (auto j : i)
printf("%d ", j); // expect: [[1]]
printf("\n");
}
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