1502_CanMakeArithmeticProgressionFromSequence - a920604a/leetcode GitHub Wiki

class Solution {
public:
    bool canMakeArithmeticProgression(vector<int>& arr) {
        sort(arr.begin(), arr.end());
        int n = arr.size(), diff = arr[1]-arr[0];
        for(int i=1;i<n;++i){
            if(arr[i]-arr[i-1] != diff) return false;
        }
        return true;
    }
};

class Solution {
public:
    bool canMakeArithmeticProgression(vector<int>& arr) {
        int n = arr.size(), mn = INT_MAX, mx = INT_MIN;
        unordered_set<int> s;
        for(int a:arr){
            mn = min(a, mn);
            mx = max(a, mx);
            s.insert(a);
        }
        int diff = (mx-mn)/(n-1), cur = mn;
        while(n--){
            if(s.find(cur)==s.end()) return false;
            cur+=diff;
        }
        return true;
    }
};