s0047

src/s0047_permutations_ii.cpp

@@ -0,0 +1,33 @@
+#include "s0047_permutations_ii.hpp"
+
+void permuteUniqueDFS(vector<int> &path, vector<vector<int>> &result,
+                      vector<bool> &used, vector<int> &nums, int startIndex) {
+  int len = nums.size();
+  // 终止条件
+  if (path.size() == len) {
+    result.push_back(path);
+    return;
+  }
+
+  // 开始迭代
+  for (int i{0}; i < len; ++i) {
+    // 如果当前元素在树层使用过，则跳过
+    if (used[i] || (i > 0 && nums[i] == nums[i - 1] && used[i - 1] == false))
+      continue;
+    // 否则处理当前节点
+    path.push_back(nums[i]);
+    used[i] = true;
+    permuteUniqueDFS(path, result, used, nums, i + 1);
+    used[i] = false;
+    path.pop_back();
+  }
+}
+
+vector<vector<int>> S0047::permuteUnique(vector<int> &nums) {
+  vector<int> path{};
+  vector<vector<int>> result{};
+  vector<bool> used(nums.size(), false);
+  sort(nums.begin(), nums.end());
+  permuteUniqueDFS(path, result, used, nums, 0);
+  return result;
+}