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Commit b8dd744

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Adds two question, one being good 2pointer question
1 parent fc1272b commit b8dd744

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2 files changed

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2 files changed

+270
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#include <bits/stdc++.h>
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using namespace std;
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// Type definitions
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typedef long long ll;
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typedef pair<int, int> pii;
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typedef pair<ll, ll> pll;
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typedef vector<int> vi;
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typedef vector<ll> vl;
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typedef vector<pii> vpii;
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typedef vector<pll> vpll;
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typedef vector<vi> vvi;
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typedef vector<vl> vvl;
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// Macros
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#define nline "\n"
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#define all(x) (x).begin(), (x).end()
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#define rall(x) (x).rbegin(), (x).rend()
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#define sz(x) (int)(x).size()
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#define pb push_back
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#define mp make_pair
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#define F first
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#define S second
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#define forn(i, n) for (int i = 0; i < int(n); i++)
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#define forr(i, a, b) for (int i = a; i <= b; i++)
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#define ford(i, a, b) for (int i = a; i >= b; i--)
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#define elasped_time 1.0 * clock() / CLOCKS_PER_SEC
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// Constants
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const int MOD = 1e9 + 7;
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const ll INF = 1e18;
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const double EPS = 1e-9;
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const double PI = acos(-1);
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ll mod_add(ll a, ll b, ll m = MOD) { return ((a % m) + (b % m)) % m; }
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ll mod_sub(ll a, ll b, ll m = MOD) { return ((a % m) - (b % m) + m) % m; }
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ll mod_mul(ll a, ll b, ll m = MOD) { return ((a % m) * (b % m)) % m; }
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ll mod_pow(ll base, ll exp, ll m = MOD)
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{
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ll res = 1;
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base %= m;
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while (exp > 0)
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{
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if (exp & 1)
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res = mod_mul(res, base, m);
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base = mod_mul(base, base, m);
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exp >>= 1;
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}
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return res;
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}
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ll mod_inv(ll a, ll m = MOD)
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{
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return mod_pow(a, m - 2, m); // Only works if m is prime
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}
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ll mod_div(ll a, ll b, ll m = MOD)
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{
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return mod_mul(a, mod_inv(b, m), m);
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}
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// Binary exponentiation (for non-modular calculations)
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ll binpow(ll base, ll exp)
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{
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ll res = 1;
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while (exp > 0)
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{
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if (exp & 1)
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res *= base;
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base *= base;
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exp >>= 1;
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}
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return res;
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}
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/************/
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void solve()
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{
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int n;
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cin >> n;
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set<int> arr;
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forn(i, n)
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{
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int x;
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cin >> x;
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arr.insert(x);
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}
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int cnt = 0, init = -1;
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for (auto it : arr)
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{
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if (init + 1 < it)
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{
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cnt++;
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init = it;
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}
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}
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cout << cnt << nline;
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}
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int main()
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{
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ios_base::sync_with_stdio(0);
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cin.tie(0);
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cout.tie(0);
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#ifndef ONLINE_JUDGE
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freopen("./outputs/input.txt", "r", stdin);
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freopen("./outputs/output.txt", "w", stdout);
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#endif
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int t;
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cin >> t;
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while (t--)
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solve();
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return 0;
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}
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// Explanation
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/*
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*/
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#include <bits/stdc++.h>
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using namespace std;
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// Type definitions
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typedef long long ll;
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typedef pair<int, int> pii;
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typedef pair<ll, ll> pll;
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typedef vector<int> vi;
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typedef vector<ll> vl;
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typedef vector<pii> vpii;
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typedef vector<pll> vpll;
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typedef vector<vi> vvi;
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typedef vector<vl> vvl;
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// Macros
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#define nline "\n"
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#define all(x) (x).begin(), (x).end()
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#define rall(x) (x).rbegin(), (x).rend()
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#define sz(x) (int)(x).size()
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#define pb push_back
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#define mp make_pair
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#define F first
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#define S second
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#define forn(i, n) for (int i = 0; i < int(n); i++)
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#define forr(i, a, b) for (int i = a; i <= b; i++)
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#define ford(i, a, b) for (int i = a; i >= b; i--)
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#define elasped_time 1.0 * clock() / CLOCKS_PER_SEC
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// Constants
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const int MOD = 1e9 + 7;
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const ll INF = 1e18;
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const double EPS = 1e-9;
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const double PI = acos(-1);
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ll mod_add(ll a, ll b, ll m = MOD) { return ((a % m) + (b % m)) % m; }
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ll mod_sub(ll a, ll b, ll m = MOD) { return ((a % m) - (b % m) + m) % m; }
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ll mod_mul(ll a, ll b, ll m = MOD) { return ((a % m) * (b % m)) % m; }
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ll mod_pow(ll base, ll exp, ll m = MOD)
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{
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ll res = 1;
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base %= m;
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while (exp > 0)
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{
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if (exp & 1)
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res = mod_mul(res, base, m);
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base = mod_mul(base, base, m);
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exp >>= 1;
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}
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return res;
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}
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ll mod_inv(ll a, ll m = MOD)
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{
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return mod_pow(a, m - 2, m); // Only works if m is prime
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}
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ll mod_div(ll a, ll b, ll m = MOD)
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{
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return mod_mul(a, mod_inv(b, m), m);
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}
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// Binary exponentiation (for non-modular calculations)
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ll binpow(ll base, ll exp)
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{
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ll res = 1;
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while (exp > 0)
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{
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if (exp & 1)
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res *= base;
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base *= base;
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exp >>= 1;
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}
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return res;
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}
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/************/
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void solve()
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{
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int n;
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cin >> n;
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vl arr(n, 0);
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forn(i, n) cin >> arr[i];
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ll tail = 0, head = -1;
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ll cost = LLONG_MAX;
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while (tail < n)
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{
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while (head + 1 < n && arr[tail] == arr[head + 1])
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{
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head++;
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}
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ll val = arr[tail];
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ll left_cost = val * tail;
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ll right_cost = val * (n - head - 1);
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ll total_cost = left_cost + right_cost;
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cost = min(cost, total_cost);
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if (tail > head)
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{
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tail++;
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head = tail - 1;
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}
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else
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{
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tail++;
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}
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}
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cout << cost << nline;
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}
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int main()
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{
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ios_base::sync_with_stdio(0);
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cin.tie(0);
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cout.tie(0);
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#ifndef ONLINE_JUDGE
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freopen("./outputs/input.txt", "r", stdin);
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freopen("./outputs/output.txt", "w", stdout);
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#endif
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int t;
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cin >> t;
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while (t--)
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solve();
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return 0;
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}
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// Explanation
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/*
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% This code solves a problem where you want to minimize a "cost" based on an array.
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% For each unique value in the array, you calculate the cost if you make all elements
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% before its segment and after its segment equal to that value.
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% The cost is: value * (number of elements before) + value * (number of elements after).
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% The code uses two pointers (tail and head) to find segments of equal values.
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% It updates the minimum cost found for all such segments.
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% At the end, it prints the smallest cost for each test case.
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% It's pretty efficient since it only scans the array once per test case.
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*/

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