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Author: ksh-code

00000000008cb0f5/0000000000ba82c5.cpp

@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+
+#pragma GCC optimize ("O3")
+#pragma GCC optimize ("Ofast")
+#pragma GCC optimize ("unroll-loops")
+#pragma GCC target("avx,avx2,fma")
+
+using namespace std;
+typedef long long ll;
+
+
+int xxxx[]={-1,0,1,0,-1,1,1,-1};
+int yyyy[]={0,1,0,-1,-1,1,-1,1};
+
+
+void solve(){
+    int N; cin >> N;
+    string str; cin >> str;
+    if (str.size() <= 2) {
+        cout << str[0];
+        return;
+    }
+    int pi[N]; memset(pi, 0, sizeof pi);
+	for (int i = 1, j = 0; i < N; i++) {
+		while (j > 0 && str[i] != str[j])
+			j = pi[j - 1];
+		if (str[i] == str[j])
+			pi[i] = ++j;
+	}
+    string pal = "";
+    for (int i = N-pi[N-1]-1; i >= 0 ; i--) pal += str[i];
+    bool found = true;
+    for (int i = 0; i < pal.size() / 2; i++) found &= pal[i] == pal[pal.size() - i - 1];
+    if (!found) pal = str[N-pi[N-1]] + pal;
+    cout << pal;
+}
+
+int main()
+{
+    cin.tie(0)->sync_with_stdio(false);
+    int T=1;
+    cin >>T;
+    for (int i = 1; i <= T; i++) {
+        cout << "Case #" << i << ": ";
+        solve();
+        cout << '\n';
+    }
+    return 0;
+}

00000000008cb0f5/0000000000ba84ae.cpp

@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+
+#pragma GCC optimize ("O3")
+#pragma GCC optimize ("Ofast")
+#pragma GCC optimize ("unroll-loops")
+#pragma GCC target("avx,avx2,fma")
+
+using namespace std;
+typedef long long ll;
+
+
+int xxxx[]={-1,0,1,0,-1,1,1,-1};
+int yyyy[]={0,1,0,-1,-1,1,-1,1};
+
+
+void solve(){
+    int N; cin >> N;
+    int arr[N]; for (auto &a: arr) cin >> a;
+    int arr2[N]; for (int i = 0; i < N; i++) arr2[i] = arr[i];
+    sort(arr2,arr2+N);
+    for (int i = 0; i < N; i++) {
+        int j = upper_bound(arr2,arr2+N, arr[i]*2) - arr2 - 1;
+        if (arr2[j]==arr[i]) j--;
+        if (j>=0&&arr2[j] <= arr[i] * 2) cout << arr2[j];
+        else cout << -1;
+        cout << ' ';
+    }
+}
+
+int main()
+{
+    cin.tie(0)->sync_with_stdio(false);
+    int T=1;
+    cin >>T;
+    for (int i = 1; i <= T; i++) {
+        cout << "Case #" << i << ": ";
+        solve();
+        cout << '\n';
+    }
+    return 0;
+}