Submission #1250396

#	Time	Username	Problem	Language	Result	Execution time	Memory
1250396		liamislazy	Triple Peaks (IOI25_triples)	C++20	0 / 100	2096 ms	1860 KiB

triples

#include "triples.h"
#include <bits/stdc++.h>
#define el '\n'
typedef long long llo;
#define fn(i,a,b) for (int i = a; i <= b; i++)
#define rn(i,a,b) for (int i = a; i >= b; i--)
using namespace std;

llo count_triples(vector<int> H)
{
    int n = H.size();
    llo ans = 0;
    //hi = k - i
    for (int i = 0; i < n; i++)
    {
        int k = i + H[i];
        if (k < 0 || k >= n) continue;
        //H[k] == j - i
        int j1 = i + H[k];
        if (j1 > i && j1 < k && j1 < n && H[j1] == k - j1) ans++;
        //H[k] == k - j
        int j2 = k - H[k];
        if (j2 > i && j2 < k && j2 < n && H[j2] == j2 - i) ans++;
    }
    //hk = k - i
    for (int k = 0; k < n; k++)
    {
        int i = k - H[k];
        if (i < 0 || i >= n) continue;
        //H[i] == j - i  => j = i + H[i], check H[j] == k - j
        int j1 = i + H[i];
        if (j1 > i && j1 < k && j1 < n && H[j1] == k - j1) ans++;
        //H[i] == k - j  => j = k - H[i], check H[j] == j - i
        int j2 = k - H[i];
        if (j2 > i && j2 < k && j2 < n && H[j2] == j2 - i) ans++;
    }
    //hj = k - i, hi = k - j, hk = j - i
    //H[i] - i = H[j] - j
    for (int j = 0; j < n; j++) {
        int c = H[j];
        for (int a = 1; a < c; a++) {
            int i = j - a;
            int k = j + (c - a);
            if (i >= 0 && k < n) {
                int b = c - a;
                if ((H[i] == a && H[k] == b) || (H[i] == b && H[k] == a)) ans++;
            }
        }
    }

    return ans;
}

std::vector<int> construct_range(int M, int K) {
    return{};
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 8
• Subtask 2: 0 / 6
• Subtask 3: 0 / 10
• Subtask 4: 0 / 11
• Subtask 5: 0 / 16
• Subtask 6: 0 / 19
• Subtask 7: 0 / 5
• Subtask 8: 0 / 5
• Subtask 9: 0 / 5
• Subtask 10: 0 / 5
• Subtask 11: 0 / 5
• Subtask 12: 0 / 5