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authorjack <[email protected]>2024-06-14 13:13:15 -0600
committerjack <[email protected]>2024-06-14 13:13:15 -0600
commitd343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch)
tree96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /combinations.cpp
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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");
+}