Submission #303949

#	Time	Username	Problem	Language	Result	Execution time	Memory
303949		rocks03	Cave (IOI13_cave)	C++14	100 / 100	250 ms	596 KiB

cave

#include "cave.h"
#include<bits/stdc++.h>
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int) (x).size())
using namespace std;

void answer(int S[], int D[]);
int tryCombination(int S[]);

pii recur(int res, int l, int r, vector<int>&v, int ans[]){
    if(l == r){
        if(res == -1){
            ans[v[l]] ^= 1;
            res = tryCombination(ans);
        }
        return {v[l], res};
    }
    int m = (l + r) / 2;
    for(int i = l; i <= m; i++){
        ans[v[i]] ^= 1;
    }
    int res2 = tryCombination(ans);
    for(int i = l; i <= m; i++){
        ans[v[i]] ^= 1;
    }
    if(res2 == res){
        return recur(res, m+1, r, v, ans);
    } else if(res2 == -1 || res2 > res){
        return recur(res, l, m, v, ans);
    } else if(res2 < res){
        for(int i = l; i <= m; i++){
            ans[v[i]] ^= 1;
        }
        pii p = recur(res2, l, m, v, ans);
        return p;
    }
}

void exploreCave(int N){
    int ans[N], d[N];
    memset(ans, 0, sizeof(ans));
    memset(d, -1, sizeof(d));
    vector<int> v(N);
    iota(v.begin(), v.end(), 0);
    while(SZ(v)){
        pii p = recur(tryCombination(ans), 0, SZ(v) - 1, v, ans);
        if(p.ss == -1){
            ans[p.ff] ^= 1;
            d[p.ff] = tryCombination(ans);
            ans[p.ff] ^= 1;
        } else{
            d[p.ff] = p.ss;
            ans[p.ff] ^= 1;
        }
        v.erase(find(v.begin(), v.end(), p.ff));
    }
    answer(ans, d);
}

Compilation message (stderr)

cave.cpp: In function 'std::pair<int, int> recur(int, int, int, std::vector<int>&, int*)':
cave.cpp:42:1: warning: control reaches end of non-void function [-Wreturn-type]
   42 | }
      | ^

• Subtask 1: 12 / 12
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 30 / 30
• Subtask 5: 24 / 24