Submission #1249624

#	Time	Username	Problem	Language	Result	Execution time	Memory
1249624		FernandoJC07	Triple Peaks (IOI25_triples)	C++20	20.65 / 100	2096 ms	2628 KiB

triples

#include <vector>
#include <functional>
#define ll long long
#define vi vector<int>
#define vl vector<ll>
#define For(i, a, n) for(int i = a; i<n; ++i)
using namespace std;

ll query13(vi H){
    int n = H.size();
    int N = n;
    function<bool(int, int, int)> triple = [&](int a, int b, int c){
    if(a>b || a>c || b>c) return false;
    if(c>=n) return false;
    if(a<0) return false;
    vi q1 = {b-a, c-b, c-a};
    vi q2 = {H[a], H[b], H[c]};
    sort(q1.begin(), q1.end());
    sort(q2.begin(), q2.end());
    return (q1 == q2);
};
    ll ans = 0;
    For(i, 0, n){
        For(j, i+1, n){
            if(H[i] == H[j]){
                if(j-i != H[i]) continue;
                int k = j+H[i];
                if(k>=N) continue;
                ans += (H[k] == 2*H[i]);
                continue;
            }
                if(j-i != H[i] && j-i != H[j]){
                int k2 = i+j+H[i]+H[j];
                if(k2&1) continue;
                k2/=2;
                if(k2>=N) continue;
                ans += (H[k2] == j-i && k2-j == min(H[i], H[j]) && k2-i == max(H[i], H[j]));
                continue;
            }
            if(j-i == H[i]){
                ans += triple(i, j, i+H[j]);
                ans += triple(i, j, j+H[j]);
            }
            else if(j-i == H[j]){
                ans += triple(i, j, i+H[i]);
                ans += triple(i, j, j+H[i]);
            }
        }
    }
    return ans;
}

ll count_triples(vi H){
    int n = H.size();
    if(n<=2000) return query13(H);
}
vi construct_range(int M, int K){
    vi ans(M);
    For(i, 0, M) if(i&1) ans[i] = 2; else ans[i]=1;
    return ans;
}

Compilation message (stderr)

triples.cpp: In function 'long long int count_triples(std::vector<int>)':
triples.cpp:56:1: warning: control reaches end of non-void function [-Wreturn-type]
   56 | }
      | ^

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 0 / 6
• Subtask 3: 10 / 10
• Subtask 4: 0 / 11
• Subtask 5: 0 / 16
• Subtask 6: 0 / 19
• Subtask 7: 1.5 / 5
• Subtask 8: 0.6225 / 5
• Subtask 9: 0.2499 / 5
• Subtask 10: 0.1071 / 5
• Subtask 11: 0.125 / 5
• Subtask 12: 0.0417 / 5