// PA 2024 3C - Akwarium
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
ios_base::sync_with_stdio(0);
int n, n2, m, cand, res;
vector<int> squares;
vector<bool> isSquare;
vector<int> prevBiggest;
cin >> n;
n2 = n * n;
for (int i = 0; i <= n2; ++i) {
isSquare.push_back(false);
prevBiggest.push_back(0);
}
for (int i = 1; i <= n; ++i) {
squares.push_back(i * i);
isSquare[i * i] = true;
prevBiggest[i * i] = i - 1;
}
m = squares.size();
for (int i = 0; i <= n2; ++i) {
if (!isSquare[i]) {
prevBiggest[i] = prevBiggest[i - 1];
}
}
res = 0;
for (int x = 0; x < m; ++x) {
for (int i = x - 1; i >= 0; --i) {
if (3 * squares[i] < squares[x]) {
break;
}
for (int j = min(i, prevBiggest[squares[x] - squares[i]]); j >= 0; --j) {
cand = squares[x] - squares[i] - squares[j];
if (cand > squares[j]) {
break;
}
if (cand > 0 && cand <= n2 && isSquare[cand]) {
//cout << "check " << squares[x] << " " << squares[i] << " " << squares[j] << " " << cand << endl;
++res;
if (i != j) {
++res;
}
if (squares[i] != cand && squares[j] != cand) {
++res;
}
}
}
}
}
/*for (int i = m - 1; i >= 0; --i) {
for (int j = i; j >= 0; --j) {
for (int k = j; k >= 0; --k) {
cand = squares[i] + squares[j] + squares[k];
if (cand > 0 && cand <= n2 && isSquare[cand]) {
//cout << "check " << squares[x] << " " << squares[i] << " " << squares[j] << " " << cand << endl;
++res;
if (i != j) {
++res;
}
if (j != k) {
++res;
}
}
}
}
}*/
cout << res;
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 | // PA 2024 3C - Akwarium #include <iostream> #include <string> #include <vector> #include <algorithm> using namespace std; int main() { ios_base::sync_with_stdio(0); int n, n2, m, cand, res; vector<int> squares; vector<bool> isSquare; vector<int> prevBiggest; cin >> n; n2 = n * n; for (int i = 0; i <= n2; ++i) { isSquare.push_back(false); prevBiggest.push_back(0); } for (int i = 1; i <= n; ++i) { squares.push_back(i * i); isSquare[i * i] = true; prevBiggest[i * i] = i - 1; } m = squares.size(); for (int i = 0; i <= n2; ++i) { if (!isSquare[i]) { prevBiggest[i] = prevBiggest[i - 1]; } } res = 0; for (int x = 0; x < m; ++x) { for (int i = x - 1; i >= 0; --i) { if (3 * squares[i] < squares[x]) { break; } for (int j = min(i, prevBiggest[squares[x] - squares[i]]); j >= 0; --j) { cand = squares[x] - squares[i] - squares[j]; if (cand > squares[j]) { break; } if (cand > 0 && cand <= n2 && isSquare[cand]) { //cout << "check " << squares[x] << " " << squares[i] << " " << squares[j] << " " << cand << endl; ++res; if (i != j) { ++res; } if (squares[i] != cand && squares[j] != cand) { ++res; } } } } } /*for (int i = m - 1; i >= 0; --i) { for (int j = i; j >= 0; --j) { for (int k = j; k >= 0; --k) { cand = squares[i] + squares[j] + squares[k]; if (cand > 0 && cand <= n2 && isSquare[cand]) { //cout << "check " << squares[x] << " " << squares[i] << " " << squares[j] << " " << cand << endl; ++res; if (i != j) { ++res; } if (j != k) { ++res; } } } } }*/ cout << res; return 0; } |
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