Leetcode-217 & 219: Contains Duplicate I & II

我的思路是用set和multiset。对219可以用类似滑动窗口的方法。

#include <iostream>
#include <vector>
#include <unordered_set>

using namespace std;

bool containsDuplicate(vector<int>& nums) {
    unordered_set<int> us;
    size_t len=nums.size();
    for (size_t i=0; i<len; ++i) {
        if (us.count(nums[i])>0) return true;
        us.insert(nums[i]);
    }
    return false;
}

bool containsNearbyDuplicate(vector<int>& nums, int k) {
    unordered_multiset<int> us;
    size_t len=nums.size();
    if (len<=1) return false;

    size_t i=0, j=1;
    us.insert(nums[0]);
    while(j<len) {
        if (j-i <= k) {
            if (us.count(nums[j])>0) return true;
            us.insert(nums[j]);
            j++;
        } else {
            us.erase(nums[i]);
            i++;
        }
    }
    return false;
}

int main()
{
    vector<int> a1={1,2,3,1};
    vector<int> a2={1,0,1,1};
    vector<int> a3={1,2,1};

    cout<<containsNearbyDuplicate(a1, 3)<<endl;
    cout<<containsNearbyDuplicate(a2, 1)<<endl;
    cout<<containsNearbyDuplicate(a3, 0)<<endl;

    return 0;
}