I am trying to solve this problem.
As far as I understood, the problem is asking to count the number of pairs such that the absolute difference between them is less than or equal to K
Based on this understanding I coded up the solution but it fails on all test cases except the first one i.e :-
SAMPLE INPUT:
7 3
10
5
1
12
9
5
14
SAMPLE OUTPUT:
5
Can someone explain what is actually asked in the problem and explain the sample test case please.
Here’s my code
// http://www.usaco.org/index.php?page=viewproblem2&cpid=643
#include <bits/stdc++.h>
// Common file
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
using ll = long long;
using pi = pair<int, int>;
using ti = tuple<int, int, int>;
using tl = tuple<ll, ll, ll>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pl = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
using vpi = vector<pi>;
using vpil = vector<pil>;
using vpli = vector<pli>;
using vpl = vector<pl>;
using vti = vector<ti>;
using vtl = vector<tl>;
using vvi = vector<vi>;
using vvl = vector<vl>;
using vvpi = vector<vpi>;
using vvpil = vector<vpil>;
using vvpli = vector<vpli>;
using vvpl = vector<vpl>;
using vvti = vector<vti>;
using vvtl = vector<vtl>;
using oset = tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>;
using omset = tree<pair<int,int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int INF = INT_MAX;
const ll LINF = LLONG_MAX;
const int MOD = 1000000000 + 7;
#define setbits(n) __builtin_popcount(n)
#define len(x) (int)size(x)
void setIO(string name = "") {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
if (len(name)) {
ignore = freopen((name + ".in").c_str(), "r", stdin);
ignore = freopen((name + ".out").c_str(), "w", stdout);
}
}
const int N = (int) 5e4;
int a[N];
int main() {
/* setIO("diamond"); */
int n, k;
cin >> n >> k;
for (int i = 0; i < n; i++) {
cin >> a[i];
}
sort(a, a + n);
for (int i = 0; i < n; i++) {
cout << a[i] << "\n";
}
int j = 0;
ll ans = 0;
for (int i = 0; i < n; i++) {
while (j < i and a[i] - a[j] > k) {
j++;
}
cout << "adding " << i-j << endl;
ans += i - j;
}
cout << ans << "\n";
return 0;
}