Submission #1307823

#	Time	Username	Problem	Language	Result	Execution time	Memory
1307823		exoworldgd	Triple Peaks (IOI25_triples)	C++20	70.51 / 100	534 ms	78164 KiB

triples

#include <bits/stdc++.h>
#define exoworldgd cin.tie(0)->sync_with_stdio(0),cout.tie(0)
using namespace std;
using ll=long long;
ll count_triples(vector<int>h){
    int n=h.size();
    set<set<int>>triples;
    auto check=[&](int i,int j){
        for(int id:{i,j})for(int dist:{h[i],h[j]})for(int k:{id-dist,id+dist})if(k>=0&&k<n&&k^i&&k^j){
            vector<int>a={h[i],h[j],h[k]},b={abs(i-j),abs(i-k),abs(j-k)};
            sort(a.begin(),a.end()),sort(b.begin(),b.end());
            if(a==b)triples.insert({i,j,k});
        }
    };
    for(int i=0;i<n;i++)for(int j:{i-h[i],i+h[i]})if(j>=0&&j<n)check(i,j);
    int ans=triples.size();
    map<int,vector<int>>d1,d2;
    for(int i=0;i<n;i++)d1[i+h[i]].push_back(i),d2[i-h[i]].push_back(i);
    for(int j=0,z;j<n;j++){
        auto&x=d1[j+h[j]],&y=d2[j-h[j]];
        if(x.size()<y.size())for(int k:x)z=k-h[j],ans+=(z>=0&&z<j&&j<k&&k<n&&h[z]==k-j&&h[j]==k-z&&h[k]==j-z&&h[z]^h[k]);
        else for(int i:y)if(i<j)z=i+h[j],ans+=(i>=0&&i<j&&j<z&&z<n&&h[i]==z-j&&h[j]==z-i&&h[z]==j-i&&h[i]^h[z]);
    }
    return ans;
}
vector<int>construct_range(int M,int K){return{4,1,4,3,2,6,1};}

• 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: 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