Submission #199832

#	Time	Username	Problem	Language	Result	Execution time	Memory
199832		Mercenary	Flood (IOI07_flood)	C++14	100 / 100	101 ms	13812 KiB

flood

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>

#define pb push_back
#define mp make_pair
#define taskname "A"

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef tree <int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;

const int maxn = 2e5 + 5;
int n , m;
int d[maxn][4];
ii a[maxn];
vector<int> res;
ii b[maxn];

int dir(int x , int y){
    if(a[x].first == a[y].first){
        if(a[x].second < a[y].second)return 0;
        else return 2;
    }
    if(a[x].first < a[y].first)return 1;
    return 3;
}

bool vis[maxn];
int flag = 0;

void dfs(int u , int dir){
    if(vis[u]){
        flag = u;return;
    };
    vis[u] = 1;
    for(int i = 5 ; i >= 2 ; --i){
        int cur = (dir + i) % 4;
        if(!d[u][cur])continue;
        int c = d[u][cur];
        int v = b[c].first + b[c].second - u;
        d[u][cur] = d[v][(cur + 2) % 4] = 0;
        dfs(v , cur);
        if(!flag){
            res.pb(c);
            continue;
        }
        if(flag != u){
            vis[u] = 0;
            return;
        }
    }
    flag = 0;
    vis[u] = 0;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if(fopen(taskname".INP","r")){
		freopen(taskname".INP", "r",stdin);
		freopen(taskname".OUT", "w",stdout);
    }
    cin >> n;
    vector<int> val(n);iota(val.begin(),val.end(),1);
    for(int i = 1 ; i <= n ; ++i)cin >> a[i].first >> a[i].second;
    sort(val.begin(),val.end(),[&](int x , int y){return a[x] < a[y];});
    cin >> m;
    for(int i = 1 ; i <= m ; ++i){
        cin >> b[i].first >> b[i].second;
        d[b[i].first][dir(b[i].first,b[i].second)] = i;
        d[b[i].second][dir(b[i].second,b[i].first)] = i;
    }
    for(auto & c : val)dfs(c,0);
    cout << res.size() << '\n';for(auto & c : res)cout << c << '\n';
}

Compilation message (stderr)

flood.cpp: In function 'int main()':
flood.cpp:66:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen(taskname".INP", "r",stdin);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
flood.cpp:67:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen(taskname".OUT", "w",stdout);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 3 / 3
• Subtask 5: 10 / 10
• Subtask 6: 3 / 3
• Subtask 7: 3 / 3
• Subtask 8: 3 / 3
• Subtask 9: 3 / 3
• Subtask 10: 9 / 9
• Subtask 11: 9 / 9
• Subtask 12: 9 / 9
• Subtask 13: 9 / 9
• Subtask 14: 9 / 9