Merge branch 'main' into main

Author: Dheeraj-06

.DS_Store

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+.vscode/ 

.gitignore

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+//#include <bits/stdc++.h>
+#include <iostream>
+#include <vector>
+#include <string>
+#include <algorithm>
+#include <map>
+#include <set>
+#include <unordered_map>
+#include <queue>
+#include <stack>
+#include <cmath>
+#include <climits>
+#define int long long
+#define fo(n) for (int i = 0; i < n; i++)
+#define fo1(ii, n) for(int i=ii; i<n; i++)
+#define all(x) x.begin(), x.end()
+#define rall(x) x.rbegin(), x.rend()
+#define pb push_back
+#define fi first
+#define se second
+#define vec(a) vector<int> a
+#define vecn(a,n) vector<int> a(n)
+#define py cout<<"YES"<<endl
+#define pn cout<<"NO"<<endl
+const int MOD = 1e9 + 7;
+const int INF = 1e18;
+using namespace std;
+
+void solve(){
+    int a,b,c;
+    cin>>a>>b>>c;
+    //a->b
+    //c->?
+    int total=abs(a-b)*2;
+    int half=total/2;
+    if(max({a,b,c})>total){
+        cout<<-1<<endl;
+        return;
+    }
+    else if(c<=total){
+        if(c>half){
+            cout<<c-half<<endl;
+        }
+        else cout<<c+half<<endl;
+    }
+}
+
+signed main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(0);
+    int t;
+    cin >> t;
+    while(t--)
+        solve();
+    return 0;
+}

Problems/.DS_Store

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+#include <bits/stdc++.h>
+using namespace std;
+
+static const int maxi = 100000;
+int spf[maxi + 1];
+int k;
+
+/*sieve*/
+void buildSPF() {
+    for (int i = 1; i <= maxi; i++)
+        spf[i] = i;
+
+    for (int i = 2; i * i <= maxi; i++) {
+        if (spf[i] == i) {
+            for (int j = i * i; j <= maxi; j += i) {
+                if (spf[j] == j)
+                    spf[j] = i;
+            }
+        }
+    }
+}
+
+/*factorise*/
+vector<pair<int,int>> getSignature(int x) {
+    map<int,int> factors;
+
+    while (x > 1) {
+        int p = spf[x];
+        factors[p]++;
+        x /= p;
+    }
+
+    vector<pair<int,int>> sig;
+    for (auto &it : factors) {
+        int exp = it.second % k;
+        if (exp != 0)
+            sig.push_back({it.first, exp});
+    }
+    return sig;
+}
+
+/*how many needed*/
+vector<pair<int,int>> getComplement(const vector<pair<int,int>> &sig) {
+    vector<pair<int,int>> comp;
+    for (auto &p : sig) {
+        comp.push_back({p.first, (k - p.second) % k});
+    }
+    return comp;
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n;
+    cin >> n >> k;
+
+    vector<int> a(n);
+    for (int i = 0; i < n; i++)
+        cin >> a[i];
+
+    buildSPF();
+
+    map<vector<pair<int,int>>, long long> freq;
+    long long ans = 0;
+
+    for (int i = 0; i < n; i++) {
+        vector<pair<int,int>> sig = getSignature(a[i]);
+        vector<pair<int,int>> need = getComplement(sig);
+        ans += freq[need];
+        freq[sig]++;
+    }
+    cout << ans << "\n";
+    return 0;
+}
+//https://codeforces.com/problemset/submission/1225/355302622
+//time  complexity O(nlognlog(10^5))

Problems/Mathematics/.DS_Store

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+/* Submission Link - https://codeforces.com/problemset/submission/1560/355259349
+Problem: Codeforces 1560B - Who's Opposite?
+
+Explanation:
+
+People are standing on a circle, numbered from 1 to n (n is even).
+Each person looks at the person exactly opposite them on the circle.
+
+Key observation:
+If a person at position x looks at position y, then the distance between
+them along the circle must be exactly n/2.
+
+Given:
+a looks at b
+=> |a - b| = n/2
+
+So the total number of people in the circle must be:
+n = 2 * |a - b|
+
+Validity check:
+All positions a, b, and c must lie within the range [1, n].
+If max(a, b, c) > n, then such a circle is impossible → output -1.
+
+Finding who c looks at:
+The opposite position of c is c + (n/2).
+If this exceeds n, we wrap around the circle by subtracting n.
+
+Edge case:
+If a == b, then |a - b| = 0 → invalid (no circle possible).
+
+Algorithm:
+1. Compute diff = |a - b|
+2. Set n = 2 * diff
+3. If diff == 0 or max(a, b, c) > n → print -1
+4. Else compute d = c + diff
+   If d > n, d -= n
+5. Print d
+
+Time Complexity: O(1) per test case
+Space Complexity : O(1) as number of test cases are fixed */
+
+#include <bits/stdc++.h>
+using namespace std;
+ 
+int main(){
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+ 
+    int t;
+    cin >> t;
+    while(t--){
+        long long a, b, c;
+        cin >> a >> b >> c;
+ 
+        long long diff = llabs(a - b);
+        long long n = 2 * diff;
+ 
+        if(diff == 0 || max({a, b, c}) > n){
+            cout << -1 << "\n";
+        } else {
+            long long d = c + diff;
+            if(d > n) d -= n;
+            cout << d << "\n";
+        }
+    }
+    return 0;
+}