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Author: coderpheonix

217.Contains Duplicate.cpp

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+#include <unordered_set>
+#include <vector>
+
+using namespace std;
+
+class Solution {
+public:
+    bool containsDuplicate(vector<int>& nums) {
+        unordered_set<int> seen;
+
+        for (int num : nums) {
+            if (seen.count(num)) return true; // Found a duplicate
+            seen.insert(num);
+        }
+
+        return false; // No duplicates found
+    }
+};
+
+
+
+
+
+
+
+class Solution {
+public:
+    bool containsDuplicate(vector<int>& nums) {
+        sort(nums.begin(), nums.end()); // O(n log n)
+
+        for (int i = 1; i < nums.size(); i++) {
+            if (nums[i] == nums[i - 1]) return true;
+        }
+
+        return false;
+    }
+};
+
+
+
+
+
+
+class Solution {
+public:
+    bool containsDuplicate(vector<int>& nums) {
+        sort(nums.begin(), nums.end()); // O(n log n)
+
+        int left = 0;
+        int right = 1; // Start from second element
+
+        while (right < nums.size()) {
+            if (nums[left] == nums[right]) {
+                return true; // Duplicate found
+            }
+            left++;
+            right++;
+        }
+
+        return false; // No duplicates
+    }
+};