Submission #1208430

#	Time	Username	Problem	Language	Result	Execution time	Memory
1208430		CodeLakVN	Pictionary (COCI18_pictionary)	C++20	140 / 140	60 ms	23108 KiB

pictionary

#include <bits/stdc++.h>
using namespace std;

#define task "main"
#define no "NO"
#define yes "YES"
#define F first
#define S second
#define vec vector
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)

template<class X, class Y>
    bool maximize(X &x, Y y) {
        if (x < y) {
            x = y;
            return true;
        }
        return false;
    }

const int MAX_N = (int)1e5 + 5;

int numNode, numDay, numQuery;

struct DSU {
    int par[MAX_N], sz[MAX_N];

    void init() {
        FOR(i, 1, numNode) par[i] = i, sz[i] = 1;
    }

    int get(int a) {
        return (a == par[a] ? a : par[a] = get(par[a]));
    }

    bool unite(int u, int v) {
        u = get(u), v = get(v);
        if (u == v) return false;
        if (sz[u] < sz[v]) swap(u, v);
        sz[u] += sz[v];
        par[v] = u;
        return true;
    }
} dsu;

vector<ii> MST[MAX_N];

struct LCA {
    int par[20][MAX_N], maxVal[20][MAX_N], high[MAX_N];

    void dfs(int u, int p) {
        for (ii e : MST[u]) {
            int v = e.F, w = e.S;
            if (v == p) continue;
            par[0][v] = u;
            maxVal[0][v] = w;
            high[v] = high[u] + 1;
            dfs(v, u);
        }
    }

    void setup() {
        dfs(1, -1);
        FOR(i, 1, 18) FOR(u, 1, numNode) {
            par[i][u] = par[i - 1][par[i - 1][u]];
            maxVal[i][u] = max(maxVal[i - 1][u], maxVal[i - 1][par[i - 1][u]]);
        }
        high[0] = -1;
    }

    int getMax(int u, int v) {
        if (high[u] < high[v]) swap(u, v);
        int ans = 0;
        FOD(i, 18, 0) if (high[par[i][u]] >= high[v]) {
            maximize(ans, maxVal[i][u]);
            u = par[i][u];
        }
        if (u == v) return ans;
        FOD(i, 18, 0) if (par[i][u] != par[i][v]) {
            maximize(ans, maxVal[i][u]);
            maximize(ans, maxVal[i][v]);
            u = par[i][u];
            v = par[i][v];
        }
        maximize(ans, maxVal[0][u]);
        maximize(ans, maxVal[0][v]);
        return ans;
    }
} lca;

void solve() {
    cin >> numNode >> numDay >> numQuery;
    dsu.init();
    FOD(i, numDay, 1) {
        for (int j = i + i; j <= numNode; j += i) {
            if (dsu.unite(i, j)) {
                MST[i].push_back({j, numDay - i + 1});
                MST[j].push_back({i, numDay - i + 1});
            }
        }
    }
    lca.setup();
    while (numQuery--) {
        int a, b;
        cin >> a >> b;
        cout << lca.getMax(a, b) << "\n";
    }
}

int32_t main() {
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    bool multitest = 0;
    int numTest = 1;
    if (multitest) cin >> numTest;

    while (numTest--) {
        solve();
    }

    return 0;
}

/* Lak lu theo dieu nhac!!!! */

Compilation message (stderr)

pictionary.cpp: In function 'int32_t main()':
pictionary.cpp:118:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  118 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
pictionary.cpp:119:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  119 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 14 / 14
• Subtask 3: 14 / 14
• Subtask 4: 14 / 14
• Subtask 5: 14 / 14
• Subtask 6: 14 / 14
• Subtask 7: 14 / 14
• Subtask 8: 14 / 14
• Subtask 9: 14 / 14
• Subtask 10: 14 / 14