Submission #1288027

#	Time	Username	Problem	Language	Result	Execution time	Memory
1288027		nikoloz-ch	Triple Peaks (IOI25_triples)	C++20	18.51 / 100	48 ms	2372 KiB

triples

#include <bits/stdc++.h>
using namespace std;

long long count_triples(std::vector<int> H){
    int N = H.size(), ans = 0;
    if(N <= 5000){
        map<int,vector<int>> mp;
        for(int i = 0; i < N; i++){
            mp[i-H[i]].push_back(i);
        }
        for(int i = 0; i < N; i++){
            for(int j = i+1; j < N; j++){
                const int k = j-i;
                if(k != H[i] and k != H[j]){
                    if(k != abs(H[i]-H[j])) continue;
                    const int p = j+min(H[i],H[j]);
                    if(p >= N or H[p] != k or p <= j) continue;
                    ans++;
                    continue;
                }
                if(k == H[i]){
                    for(auto &t : mp[i]){
                        if(t <= j) continue;
                        if(t-j != H[j]) continue;
                        ans++;
                    }
                    for(auto &t : mp[j]){
                        if(t <= j) continue;
                        if(t-i != H[j]) continue;
                        ans++;
                    }
                    continue;
                }
                for(auto &t : mp[i]){
                    if(t <= j) continue;
                    if(abs(t-j) != H[i]) continue;
                    ans++;
                }
                for(auto &t : mp[j]){
                    if(t <= j) continue;
                    if(abs(t-i) != H[i]) continue;
                    ans++;
                }
                continue;
            }
        }
        return ans;
    }
    for(int i = 0; i < N-20; i += 20){
        vector<int> a;
        for(int j = i; j <= i+20; j++){
            a.push_back(H[j]);
        }
        ans += count_triples(a);
    }
    return ans;
}


std::vector<int> construct_range(int M, int K){
    vector<int> a;
    return {4, 1, 4, 3, 2, 6, 1};
}

• 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: 0.5 / 5
• Subtask 8: 0.0075 / 5
• Subtask 9: 0.0003 / 5
• Subtask 10: 0 / 5
• Subtask 11: 0 / 5
• Subtask 12: 0 / 5