Competitive-Programming/D_Range_sum.cpp at main · MohnishK7/Competitive-Programming · GitHub

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

#define MOD 1000000007
#define MOD1 998244353
#define INF 1e18
#define nline "\n"
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define set_bits __builtin_popcountll
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()

typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
// typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update > pbds; // find_by_order, order_of_key

#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif

void _print(ll t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}

template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

/*--------------------------------------------------------------------------------------------------------------------------------------*/

int main() {
#ifndef ONLINE_JUDGE
   //input.txt
   freopen("input1.txt", "r", stdin);
   //output.txt
   freopen("output1.txt", "w", stdout);
   //error
   freopen("error.txt", "w", stderr);
#endif
   ios_base::sync_with_stdio(false);
   cin.tie(0);

   // code here
   // int tc;
   // cin >> tc;
   // int cnt = 0;
   // while (tc--) {
   //    int l, r;
   //    cin >> l >> r;
   //    for (int i = x; i <= y; i++) {
   //       cnt = cnt + i;
   //    }
   //    cout << cnt << "\n";
   // }
   // ll tc;
   // cin >> tc;
   // while (tc--) {
   //    ll sum = 0;
   //    ll x;
   //    ll y;
   //    cin >> x >> y;
   //    for (int i = x; i <= y; i++) {
   //       debug(sum);
   //       sum = sum + i;
   //    }
   //    cout << sum << "\n";
   // }
   ll tc;
   cin >> tc;
   while (tc--) {
      ll l, r;
      cin >> l >> r;
      ll maxi = max(l, r);
      ll mini = min(l, r);
      mini --;
      ll r1 = mini * (mini + 1) / 2;
      ll r2 = maxi * (maxi + 1) / 2;

      cout << r2 - r1 << "\n";
   }

   return 0;
}