HackerRank Warm-up 1.Sales by Match, in C++

題目連結：Sales by Match | HackerRank

因應HackerRank系統，而分享 Coding 核心部分

int sockMerchant(int n, vector<int> ar) {
    int ct[105]{0};
    for(auto a:ar){
        ct[a]++;
    }
    int ans=0;
    for(int i=0;i<105;i++){
        ans+=ct[i]/2;
    }
    return ans;
}