Submission #44497

#	Time	Username	Problem	Language	Result	Execution time	Memory
44497		nickyrio	Gift (IZhO18_nicegift)	C++17	100 / 100	851 ms	155112 KiB

nicegift

/* 
Condition: 
    - Sum of arrays must be divisible by k
    - Maximum number must be smaller than or equal to (sum / k) 
Solution:
    - Divide array into k blocks
    - ....
*/
#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define DEBUG(x) { cerr << #x << '=' << x << endl; }
#define Arr(a, l, r) { cerr << #a << " = {"; FOR(_, l, r) cerr << ' ' << a[_]; cerr << "}\n"; }
#define N 1001000
#define pp pair<long long, int>
#define endl '\n'
#define IO ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define taskname ""
#define bit(S, i) (((S) >> (i)) & 1)
using namespace std;

int n, k;
vector< vector<pp> > block;
vector< vector<long long> > res;
long long a[N];

int main() {
    #ifdef NERO
    freopen("test.inp","r",stdin);
    freopen("test.out","w",stdout);
    double stime = clock();
    #else 
        //freopen(taskname".inp","r",stdin);
        //freopen(taskname".out","w",stdout);
    #endif //NERO
    IO;
    cin >> n >> k;
    long long sum = 0, mx = 0;
    FOR(i, 1, n) {
        cin >> a[i];
        mx = max(mx, a[i]);
        sum += a[i];
    }
    long long average = (sum / k);
    if (sum % k || mx > average) {
        cout << -1;
        return 0;
    }
    vector<pp> now;
    long long temp = 0;
    FOR(i, 1, n) {
        temp += a[i];
        if (temp >= average) {
            now.push_back(pp(a[i] - (temp - average), i));
            block.push_back(now);
            temp -= average;
            now.clear();
            if (temp) now.push_back(pp(temp, i));
        } else now.push_back(pp(a[i], i));
    }
    while (sum > 0) {
        vector<long long> ans;
        long long subtract = 1e18;
        REP(i, k) subtract = min(subtract, block[i].back().first);
        sum -= subtract * k;
        ans.push_back(subtract);
        REP(i, k) {
            block[i].back().first -= subtract;
            ans.push_back(block[i].back().second);
            if (block[i].back().first == 0) block[i].pop_back();
        }
        res.push_back(ans);
    }
    cout << (int) res.size() << '\n';
    REP(i, res.size()) {
        for (long long x : res[i]) cout << x << ' '; cout << '\n';
    }
    #ifdef NERO
    double etime = clock();
    cerr << "Execution time: " << (etime - stime) / CLOCKS_PER_SEC * 1000 << " ms.\n";
    #endif // NERO
}

Compilation message (stderr)

nicegift.cpp: In function 'int main()':
nicegift.cpp:12:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define REP(i, a) for (int i = 0; i < (a); ++i)
                                     ^
nicegift.cpp:76:5: note: in expansion of macro 'REP'
     REP(i, res.size()) {
     ^~~
nicegift.cpp:77:9: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
         for (long long x : res[i]) cout << x << ' '; cout << '\n';
         ^~~
nicegift.cpp:77:54: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
         for (long long x : res[i]) cout << x << ' '; cout << '\n';
                                                      ^~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 51 / 51