#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> #ifdef LOCAL #include "../debug/debug.h" #else #define debug(...) #define debugArr(...) #endif using namespace std; using namespace __gnu_pbds; using ll = long long; using db = long double; using pi = pair<int,int>; using pl = pair<ll,ll>; using vi = vector<int>; using vl = vector<ll>; using vb = vector<bool>; using vpi = vector<pi>; using vpl = vector<pl>; using vvi = vector<vi>; #define mp make_pair #define eb emplace_back #define pb push_back #define x first #define y second #define sz(x) int((x).size()) #define bg(x) begin(x) #define all(x) (x).begin(),(x).end() #define rall(x) (x).rbegin(), (x).rend() #define rep(i,a,b) for(int i=(a);i<(b);i++) #define per(i,a,b) for(int i=(b)-1;i>=(a);i--) #define ft front() #define bk back() #define rsz resize #define ins insert #define each(a,x) for(auto&a:x) template<class T> bool ckmin(T& a, T b) { return b<a?a=b,1:0; } template<class T> bool ckmax(T& a, T b) { return b>a?a=b,1:0; } template<class T> int lwb(vector<T>& a, const T& b) { return int(lower_bound(all(a),b)-bg(a)); } template<class T> int upb(vector<T>& a, const T& b) { return int(upper_bound(all(a),b)-bg(a)); } template<class T> void remdup(vector<T>& v) { sort(all(v)); v.erase(unique(all(v)),end(v)); } constexpr int pct(int x) { return __builtin_popcount(x); } constexpr int bitlog(int x) { return x == 0 ? 0 : 31 - __builtin_clz(x); } constexpr int pct(ll x) { return __builtin_popcountll(x); } constexpr int bitlog(ll x) { return x == 0 ? 0 : 63 - __builtin_clzll(x); } constexpr ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up constexpr ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); } // divide a by b rounded down constexpr int cdiv(int a, int b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded down constexpr int fdiv(int a, int b) { return a / b - ((a ^ b) < 0 && a % b); } // divide a by b rounded down const pi MOVES[] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}}; #ifdef LOCAL mt19937_64 rng(0xabadbeef); #else mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); #endif ll randr(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rng); } int n; int res; vi divs; signed main() { cin.tie(0)->sync_with_stdio(0); cin >> n; divs.resize(n * n + 1); rep(i,1,n+1) { int j = i * (i + 2); int c = i + 1; while (j <= n * n && c <= n) { divs[j]++; c++; j += 2 * i; } } for (int a = 1; a <= n; a++) { int a2 = a * a; for (int b = a; a <= b; b++) { int b2 = b * b; int sum = a2 + b2; if (sum > n * n) break; res += divs[sum]; } } cout << res << '\n'; 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 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 | #include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> #ifdef LOCAL #include "../debug/debug.h" #else #define debug(...) #define debugArr(...) #endif using namespace std; using namespace __gnu_pbds; using ll = long long; using db = long double; using pi = pair<int,int>; using pl = pair<ll,ll>; using vi = vector<int>; using vl = vector<ll>; using vb = vector<bool>; using vpi = vector<pi>; using vpl = vector<pl>; using vvi = vector<vi>; #define mp make_pair #define eb emplace_back #define pb push_back #define x first #define y second #define sz(x) int((x).size()) #define bg(x) begin(x) #define all(x) (x).begin(),(x).end() #define rall(x) (x).rbegin(), (x).rend() #define rep(i,a,b) for(int i=(a);i<(b);i++) #define per(i,a,b) for(int i=(b)-1;i>=(a);i--) #define ft front() #define bk back() #define rsz resize #define ins insert #define each(a,x) for(auto&a:x) template<class T> bool ckmin(T& a, T b) { return b<a?a=b,1:0; } template<class T> bool ckmax(T& a, T b) { return b>a?a=b,1:0; } template<class T> int lwb(vector<T>& a, const T& b) { return int(lower_bound(all(a),b)-bg(a)); } template<class T> int upb(vector<T>& a, const T& b) { return int(upper_bound(all(a),b)-bg(a)); } template<class T> void remdup(vector<T>& v) { sort(all(v)); v.erase(unique(all(v)),end(v)); } constexpr int pct(int x) { return __builtin_popcount(x); } constexpr int bitlog(int x) { return x == 0 ? 0 : 31 - __builtin_clz(x); } constexpr int pct(ll x) { return __builtin_popcountll(x); } constexpr int bitlog(ll x) { return x == 0 ? 0 : 63 - __builtin_clzll(x); } constexpr ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up constexpr ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); } // divide a by b rounded down constexpr int cdiv(int a, int b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded down constexpr int fdiv(int a, int b) { return a / b - ((a ^ b) < 0 && a % b); } // divide a by b rounded down const pi MOVES[] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}}; #ifdef LOCAL mt19937_64 rng(0xabadbeef); #else mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); #endif ll randr(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rng); } int n; int res; vi divs; signed main() { cin.tie(0)->sync_with_stdio(0); cin >> n; divs.resize(n * n + 1); rep(i,1,n+1) { int j = i * (i + 2); int c = i + 1; while (j <= n * n && c <= n) { divs[j]++; c++; j += 2 * i; } } for (int a = 1; a <= n; a++) { int a2 = a * a; for (int b = a; a <= b; b++) { int b2 = b * b; int sum = a2 + b2; if (sum > n * n) break; res += divs[sum]; } } cout << res << '\n'; return 0; } |