Submission #714792

#	Time	Username	Problem	Language	Result	Execution time	Memory
714792		Toxtaq	Stranded Far From Home (BOI22_island)	C++17	20 / 100	1096 ms	290088 KiB

island

#include <bits/stdc++.h>
using namespace std;
vector<vector<int>>g;
vector<int>num;
vector<long long>cnt1;
vector<int>canTraverse; /// 0-unchecked, 1-false, 2-true
void calc(int u, int par){
    cnt1[u] = num[u];
    for(int v : g[u]){
        if(v != par){
            calc(v, u);
            cnt1[u] += cnt1[v];
        }
    }
}
void dfs1(int u, int par){
    if(canTraverse[par] == 1)canTraverse[u] = 1;
    else{
        canTraverse[u] = (cnt1[u] >= num[par]) + 1;
    }
    for(int v : g[u]){
        if(v != par){
            dfs1(v, u);
        }
    }
}
vector<bool>vis, chosen;
bool cmp(int a, int b){
    return num[a] < num[b];
}
long long cnt = 0;
vector<int>tmp;
void dfs(int u){
    vis[u] = 1;
//    cout << u << " ";
    vector<int>tempo;
    for(int v : g[u]){
        if(!chosen[v] && cnt >= num[v]){
            cnt += num[v];
            chosen[v] = 1;
            tempo.push_back(v);
        }
        else if(cnt < num[v]){
            tmp.push_back(v);
        }
    }
    for(int v : tempo){
        if(!vis[v]){
            dfs(v);
        }
    }
}
int main()
{
    int n, m;
    cin >> n >> m;
    if(n <= 2000 && m <= 2000){
        g.resize(n + 1);
        num.resize(n + 1);
        vis.resize(n + 1);
        chosen.resize(n + 1);
        for(int i = 1;i <= n;++i)cin >> num[i];
        for(int i = 0;i < m;++i){
            int u, v;
            cin >> u >> v;
            g[u].push_back(v);
            g[v].push_back(u);
        }
        for(int i = 1;i <= n;++i){
            sort(g[i].begin(), g[i].end(), cmp);
        }
    //    for(int i = 1;i <= n;++i){
    //        cout << i << ": ";
    //        for(int j : g[i]){
    //            cout << j << " ";
    //        }
    //        cout << '\n';
    //    }
        string s = "";
        for(int i = 1;i <= n;++i){
    //        cout << i << ": ";
            cnt = num[i];
            chosen[i] = 1;
            dfs(i);
            sort(tmp.begin(), tmp.end(), cmp);
            int ind = 0;
            while(tmp.size() && ind < tmp.size()){
                int j = tmp[ind], sz = tmp.size();
                if(!chosen[j] && cnt >= num[j]){
                    chosen[j] = 1;
                    cnt += num[j];
                    dfs(j);
                }
                else{
                    ind++;
                    continue;
                }
                sort(tmp.begin(), tmp.end(), cmp);
                ind = 0;
            }
    //        cout << "CNT: " << cnt << '\n';
            bool ok = 1;
            for(int j = 1;j <= n && ok;++j){
                if(!vis[j]){
                    ok = 0;
                }
            }
            for(int j = 1;j <= n;++j){
                vis[j] = 0;
                chosen[j] = 0;
            }
            if(ok)s += '1';
            else s += '0';
            tmp.clear();
        }
        cout << s;
    }
    else{
        g.resize(n + 1);
        num.resize(n + 1);
        cnt1.resize(n + 1);
        canTraverse.resize(n + 1);
        for(int i = 1;i <= n;++i){
            cin >> num[i];
        }
        for(int i = 0;i < m;++i){
            int u, v;
            cin >> u >> v;
            g[u].push_back(v);
            g[v].push_back(u);
        }
        calc(1, 1);
        dfs1(1, 1);
        for(int i = 1;i <= n;++i){
            if(canTraverse[i] == 2)cout << 1;
            else cout << 0;
        }
    }

}

Compilation message (stderr)

island.cpp: In function 'int main()':
island.cpp:87:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |             while(tmp.size() && ind < tmp.size()){
      |                                 ~~~~^~~~~~~~~~~~
island.cpp:88:35: warning: unused variable 'sz' [-Wunused-variable]
   88 |                 int j = tmp[ind], sz = tmp.size();
      |                                   ^~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 30
• Subtask 5: 0 / 35