Submission #60078097

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Source Code Expand

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
#include <queue>
#include <atcoder/all>
using namespace std;

#define REP(i, n) for (int i = 0; i < n; i++)
#define FOR(i, l, r) for (int i = l; i <= r; i++)
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)

using ll = long long;
using VI = vector<int>;
using VL = vector<ll>;
using VVI = vector<VI>;
using VVL = vector<VL>;

const int INF = 1e9;

int main()
{
    int n, m = 20;
    cin >> n;
    VI a(n);
    VVI pos(m);
    REP(i,n){
        cin >> a[i];
        a[i]--;
        pos[a[i]].push_back(i);
    }
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    pq.push({0, 0});
    VI dist(1<<m, INF);
    dist[0] = 0;
    while(!pq.empty()){
        auto [d, b] = pq.top(); pq.pop();
        if(dist[b] < d) continue;
        REP(i,m){
            if ((b>>i)&1) continue;
            int x = lower_bound(pos[i].begin(), pos[i].end(), d) - pos[i].begin();
            if (x + 1 >= pos[i].size()) continue;
            int nb = b | (1<<i);
            int nd = pos[i][x+1];
            if (dist[nb] > nd){
                dist[nb] = nd;
                pq.push({nd, nb});
            }
        }
    }
    int ans = 0;
    REP(i,1<<m) {
        if (dist[i] < INF) {
            int cnt = 0;
            REP(j,m) if ((i>>j)&1) cnt++;
            chmax(ans, cnt);
        }
    }
    cout << 2*ans << endl;
    return 0;
}

Submission Info

Compile Error

Main.cpp: In function ‘int main()’:
Main.cpp:45:23: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   45 |             if (x + 1 >= pos[i].size()) continue;
      |                 ~~~~~~^~~~~~~~~~~~~~~~

Judge Result