Submission #484826

#	Time	Username	Problem	Language	Result	Execution time	Memory
484826		nhanbin03	Watermelon (INOI20_watermelon)	C++14	31 / 100	80 ms	18080 KiB

Main

#include <bits/stdc++.h>
#define task "INOI20_watermelon"
#define X first
#define Y second

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int N = 1e5 + 10;

int n, k;
int a[N], inDeg[N], ans[N], rev[N];
vector<int> adj[N], pos[N];

bool buildDAG(int maxVal) {
    for (int i = 1; i <= n; i++) {
        pos[a[i]].push_back(i);
    }
    set<int> posSet;
    for (int i = maxVal; i >= 1; i--) {
        if (pos[i].empty()) return 0;
        for (int j = pos[i].size() - 1; j >= 0; j--)  {
            int x = pos[i][j];
            auto it = posSet.lower_bound(x);
            if (it != posSet.end()) {
                adj[x].push_back(*it);
                inDeg[*it]++;
            }
            if (it != posSet.begin()) {
                it--;
                if (j == 0 || pos[i][j - 1] < *it) {
                    adj[x].push_back(*it);
                    inDeg[*it]++;
                }
            }
            posSet.insert(x);
        }
    }
    return 1;
}

void solve() {
    priority_queue<int, vector<int>, greater<int>> pq;
    for (int i = 1; i <= n; i++) {
        if (inDeg[i] == 0) {
            pq.push(i);
        }
    }
    for (int i = 1; i <= n; i++) {
        int u = pq.top(); pq.pop();
        ans[u] = i;
        for (int v : adj[u]) {
            inDeg[v]--;
            if (inDeg[v] == 0) pq.push(v);
        }
    }
    for (int i = 1; i <= n; i++) {
        assert(inDeg[i] == 0);
        rev[ans[i]] = i;
    }
}

bool findNext() {
    set<int> s;
    for (int i = n; i >= 1; i--) {
        int u = rev[i];
//        cout << i << " " << u << endl;
        for (int v : adj[u]) {
            inDeg[v]++;
            s.erase(v);
        }
//        for (auto it = s.begin(); it != s.end(); it++) cout << *it << " "; cout << endl;
        auto it = s.lower_bound(u);
        if (it != s.end()) {
            priority_queue<int, vector<int>, greater<int>> pq;
            int u = *it;
            pq.push(u);
            for (int j = i; j <= n; j++) {
                int u = pq.top(); pq.pop();
                if (j == i) {
                    pq.push(rev[i]);
//                    cout << rev[i] << endl;
                    for (auto it = s.begin(); it != s.end(); it++) {
//                        cout << *it << " ";
                        if (*it != u) pq.push(*it);
                    }
//                    cout << endl;
                }
                ans[u] = j;
                for (int v : adj[u]) {
                    inDeg[v]--;
//                    cout << u << " " << v << " " << inDeg[v] << endl;
                    if (inDeg[v] == 0) pq.push(v);
                }
            }
            return 1;
        }
        s.insert(u);
    }
    return 0;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cout.tie(0);
    if (fopen(task ".inp","r")) {
        freopen(task ".inp","r",stdin);
        freopen(task ".out","w",stdout);
    }
    cin >> n >> k;
    assert(k == 1);
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    if (a[n] != -1) {
        cout << -1;
        return 0;
    }
    int maxVal = 0;
    for (int i = 1; i <= n; i++) {
        maxVal = max(maxVal, a[i]);
    }
    for (int i = n; i >= 1; i--) {
        if (a[i] == -1) a[i] = ++maxVal;
    }
//    for (int i = 1; i <= n; i++) {
//        cout << a[i] << " ";
//    }
//    cout << "\n";
    if (!buildDAG(maxVal)) {
        cout << -1;
        return 0;
    }
//    for (int i = 1; i <= n; i++) {
//        cout << i << ": ";
//        for (int j : adj[i]) {
//            cout << j << " ";
//        }
//        cout << "\n";
//    }
    solve();
    for (int i = 1; i < k; i++) {
        if (!findNext()) {
            cout << -1;
            return 0;
        }
        for (int j = 1; j <= n; j++) {
//            cout << ans[j] << " ";
            assert(inDeg[j] == 0);
            rev[ans[j]] = j;
        }
//        cout << endl;
    }
    for (int i = 1; i <= n; i++) {
        cout << ans[i] << " ";
    }
    for (int u = 1; u <= n; u++) {
        for (int v : adj[u]) {
            if (ans[u] >= ans[v]) {
                assert(0);
            }
        }
    }
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:110:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |         freopen(task ".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:111:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  111 |         freopen(task ".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 25
• Subtask 3: 31 / 31
• Subtask 4: 0 / 18
• Subtask 5: 0 / 19