#include "triples.h"
#include <bits/stdc++.h>
using namespace std;
#define int long long
int ans = 0;
int n;
void count1(vector<signed> &h){
for (int idx = 0; idx<n; idx++){
int x = h[idx];
int idh = idx - x;
if (idh < 0) continue;
int y = h[idh] - x;
if (y <= 0 || y==x) continue;
int idy = idx + y;
if (idy >= n) continue;
if (h[idy] == y) ans++;
}
}
void count2(vector<signed> &h){
for (int idx = 0; idx<n; idx++){
int x = h[idx];
int idy = idx + x;
if (idy >= n) continue;
int y = h[idy];
int idh = idx - y;
if (idh < 0) continue;
if (h[idh] == x + y) ans++;
}
}
void count3(vector<signed> &h){
for (int idx = 0; idx<n; idx++){
int x = h[idx];
int idh = idx + x;
if (idh >= n) continue;
int y = h[idh] - x;
if (y <= 0 || y==x) continue;
int idy = idh + y;
if (idy >= n) continue;
if (h[idy] == y) ans++;
}
}
void count4(vector<signed> &h){
vector<vector<int>> tl(n);
for (int i=0; i<n; i++){
int j = i - h[i]; if (j< 0) continue;
tl[j].push_back(h[i]);
}
for (int idx=0; idx<n; idx++){
int x = h[idx];
if (idx + x >= n) continue;
for (int y: tl[idx+x]){
int idh = idx + y; if(idh>=n) continue;
if (h[idh] == x+y) ans++;
}
}
}
long long count_triples(std::vector<signed> h) {
n = h.size();
auto rh = h; reverse(rh.begin(), rh.end());
count1(h); count1(rh);
count2(h); count2(rh);
count3(h);
count4(h);
return ans;
}
std::vector<signed> construct_range(signed M, signed K) {
return {1, 1, 1};
}
