Codeforces140C New Year Snowmen

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> PII;
typedef long long LL;

int n;
struct Node {
    int r1, r2, r3;
};
vector<Node> res;
unordered_map<int, int> mp; 
priority_queue<PII> heap;

int main() {
    cin >> n;
    for (int i = 0; i < n; i++) {
        int x; scanf("%d", &x);
        mp[x]++;
    }
    for (auto item : mp) heap.push({item.second, item.first});
    int cnt = 0;
    while (heap.size() >= 3) {
        auto a = heap.top(); heap.pop();
        auto b = heap.top(); heap.pop();
        auto c = heap.top(); heap.pop();
        int ra = a.second, rb = b.second, rc = c.second;
        int t[3] = {ra, rb, rc};
        sort(t, t + 3);
        res.push_back({t[2], t[1], t[0]});
        cnt++;
        if (--a.first) heap.push(a);
        if (--b.first) heap.push(b);
        if (--c.first) heap.push(c);
    }
    cout << cnt << endl;
    for (auto x : res) printf("%d %d %d\n", x.r1, x.r2, x.r3);
    return 0;
}