287. Find the Duplicate Number
Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive.
There is only one repeated number in nums, return this repeated number.
- new solution update 2022.02.25
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| class Solution {
public:
int findDuplicate(vector<int>& nums) {
for(auto n : nums) {
int index = abs(n) - 1;
if(nums[index] < 0) return abs(n);
nums[index] = -nums[index];
}
return -1;
}
};
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| class Solution {
public:
int findDuplicate(vector<int>& nums) {
unordered_set<int> s;
for(auto& n : nums) {
if(s.count(n)) return n;
s.insert(n);
}
return -1;
}
};
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