Submission #1249619

#	Time	Username	Problem	Language	Result	Execution time	Memory
1249619		bronze_coder	Triple Peaks (IOI25_triples)	C++20	86.15 / 100	136 ms	31300 KiB

triples

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

long long count_triples(vector<int> H){
    int n = H.size();
    long long count = 0;
    for(int i=0;i<n;i++){
        int a = H[i];
        int j = i+a;
        if(j<n){
            int k;
            k = j+H[j];
            if(i<k&&k<n&&k!=j&&k-i==H[k]){
                count++;
            }
            k = i+H[j];
            if(i<k&&k<n&&k!=j&&max(k-j,j-k)==H[k]&&k!=j+H[i]){
                count++;
            }
            k = j-H[j];
            if(i<k&&k<n&&k!=j&&k-i==H[k]&&k!=i+H[j]){
                count++;
            }
        }
        j = i-a;
        if(j>=0){
            int k = i+H[j];
            if(k<n&&i-j!=H[j]&&k>j&&k-j==H[k]){
                count++;
            }
        }
    }
    vector<vector<int>> heights1(2*n);
    vector<vector<int>> heights2(2*n);
    for(int i=0;i<n;i++){
        heights1[i+H[i]].push_back(i);
        heights2[i-H[i]+n].push_back(i);
    }

    for(int i=0;i<n;i++){
        int s1 = heights1[i+H[i]].size();
        int s2 = heights2[i-H[i]+n].size();
        if(s1<s2){
            for(int j:heights1[i+H[i]]){
                if(j>i){
                    int k = i-H[j];
                    if(k>=0&&k<n&&j-i==H[k]){
                        count++;
                    }
                }
            }
        }
        else{
            for(int j:heights2[i-H[i]+n]){
                if(j<i){
                    int k = j+H[i];
                    if(k>=0&&k<n&&i-j==H[k]){
                        count++;
                    }
                }
            }
        }
    }
    return count;
}

vector<int> construct_range(int m, int k){
  if(m==20){
    return {2,1,1,3,2,3,4,1,2,1,3,1,2,1,4,3,2,3,1,1};
  }
  else{
    vector<int> x;
    vector<int> y;
    int n = 200;
    while(16*n*n+2*n>m){
      n--;
    }
    vector<int> l(m,1);
    for(int i=0;i<m;i++){
        if(i%3==0){
            l[i] = 2;
        }
    }
    for(int i=0;i<n;i++){
        x.push_back(i);
        y.push_back(i);
    }
    for(int i=0;i<3*n;i++){
        x.push_back(4*n*(i+1));
    }
    for(int i=0;i<n;i++){
        y.push_back((4*n+1)*(i+1)+n-1);
    }

    for(int i=0;i<4*n;i++){
        for(int j=0;j<2*n;j++){
            if(i>=n||j>=n){
                l[x[i]-y[j]+(4*n*n+2*n-1)] = x[i]+y[j]-(n-1);
            }
        }
    }
    return l;
  }
}

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 6 / 6
• Subtask 3: 10 / 10
• Subtask 4: 11 / 11
• Subtask 5: 16 / 16
• Subtask 6: 19 / 19
• Subtask 7: 5 / 5
• Subtask 8: 1.8675 / 5
• Subtask 9: 1.8715 / 5
• Subtask 10: 1.875 / 5
• Subtask 11: 3.7612 / 5
• Subtask 12: 1.7769 / 5