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| #include <iostream> #include <vector> #include <unordered_set> #include <algorithm> using namespace std;
class Solution_0 { public: int firstMissingPositive(vector<int>& nums) { unordered_set<int> set; for (const auto& x : nums) { set.insert(x); }
int res = 1; while (set.count(res)) { res++; }
return res; } };
class Solution { public: int firstMissingPositive(vector<int>& nums) { int n = nums.size();
for (int i = 0; i < n; i++) { while (nums[i] >= 1 && nums[i] <= n && nums[i] != i+1 && nums[i] != nums[nums[i]-1]) { swap(nums[i], nums[nums[i]-1]); } } for (int i = 0; i < n; i++) { if (nums[i] != i+1) { return i+1; } }
return n+1; } };
void printArray(const vector<int>& nums) { cout << "["; for (size_t i = 0; i < nums.size(); i++) { cout << nums[i]; if (i != nums.size() - 1) cout << ","; } cout << "]"; }
int main() { Solution solution; vector<vector<int>> nums_cases = { {1,2,0}, {3,4,-1,1}, {7,8,9,11,12}, };
for (size_t i = 0; i < nums_cases.size(); i++) { auto& nums = nums_cases[i]; cout << "Input: "; printArray(nums); cout << endl;
int result = solution.firstMissingPositive(nums); cout << "Output: " << result << endl; }
return 0; }
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