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Author: BrandonTang89

Other_Tasks/CF1993_A_Question_Marks.py

@@ -0,0 +1,8 @@
+from collections import Counter
+
+tc = int(input())
+for _ in range(tc):
+    n = int(input())
+    c = Counter(list(input()))
+    ans = sum(min(n, c[x]) for x in 'ABCD')
+    print(ans)

Other_Tasks/CF1993_B_Parity_and_Sum.py

@@ -0,0 +1,28 @@
+t = int(input())
+for _ in range(t):
+    n = int(input())
+    arr = list(map(int, input().split()))
+    
+    evens = list(filter(lambda x: x % 2 == 0, arr))
+    odds = list(filter(lambda x: x % 2 != 0, arr))
+    
+    if len(evens) == 0 or len(odds) == 0:
+        print(0)
+        continue
+
+    cur = max(odds)
+    evens.sort()
+    bigeven = evens[-1]
+    
+    ans = 0
+    for e in evens:
+        while cur < e:
+            cur += bigeven
+            ans += 1
+
+        cur += e
+        ans += 1
+    
+    print(ans)
+    
+        

Other_Tasks/CF1993_C_Light_Switches.cpp

@@ -0,0 +1,50 @@
+#pragma GCC optimize("Ofast")
+#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
+#pragma GCC optimize("unroll-loops")
+#include <bits/stdc++.h>
+using namespace std;
+
+int n, k;
+vector<int> v;
+int main() {
+    int tc;
+    cin >> tc;
+
+    while (tc--) {
+        cin >> n >> k;
+        v.assign(2 * k, 0);
+
+        int over = 0;
+        int maxq = 0;
+        int maxa = 0;
+        for (int i = 0; i < n; i++) {
+            int x;
+            cin >> x;
+            maxq = max(maxq, x / (2 * k));  // number of periods before last room activated
+            maxa = max(maxa, x);            // number of rooms activated in last period
+            x %= (2 * k);
+            v[x]++;
+            v[(x + k) % (2 * k)]--;
+            if (x >= k) over++;
+        }
+
+        int cur = over;
+        vector<int> possible(2 * k, 0);
+        for (int i = 0; i < 2 * k; i++) {
+            cur += v[i];
+            if (cur == n) possible[i] = 1;
+        }
+
+        int minTime = -1;
+        for (int i = maxa; i < maxa + k; i++) {
+            if (possible[i % (2 * k)]) {
+                minTime = i;
+                break;
+            }
+        }
+
+        cout << minTime << endl;
+    }
+
+    return 0;
+}

Other_Tasks/CF1993_D_Med_imize.cpp

@@ -0,0 +1,70 @@
+#pragma GCC optimize("Ofast")
+#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
+#pragma GCC optimize("unroll-loops")
+#include <bits/stdc++.h>
+using namespace std;
+
+#define fast_cin()                    \
+    ios_base::sync_with_stdio(false); \
+    cin.tie(NULL);                    \
+    cout.tie(NULL);
+
+int n, k;
+constexpr int inf = 1e9;
+constexpr int maxn = 5e5 + 1;
+vector<int> arr;
+vector<vector<int>> memo;
+vector<int> suffixAtLeastX;
+int totalSegments, toRemain, x;
+
+int dp(int a, int b) {  // dp(a, b) = maximum number of additional remaining elements > = x assuming that we already have a remaining numbers and used b k segments
+    if (memo[a][b] != -1) return memo[a][b];
+    if (a == toRemain) return memo[a][b] = 0;  // already collected everything
+    int idx = a + b * k;
+    if (idx == n) return memo[a][b] = 0;  // no more able to take
+    int ans = dp(a + 1, b) + (arr[idx] >= x);
+    if (idx + k < n) ans = max(ans, dp(a, b + 1));
+
+    return memo[a][b] = ans;
+}
+
+inline bool medAtLeast(int target) {  // true iff the median achieved can be at least x
+    x = target;
+    memo.assign(toRemain + 1, vector<int>(totalSegments + 1, -1));
+    return dp(0, 0) >= (toRemain + 2) / 2;
+}
+
+int main() {
+    fast_cin();
+    int tc;
+    cin >> tc;
+    arr.resize(maxn);
+    suffixAtLeastX.resize(maxn);
+    while (tc--) {
+        cin >> n >> k;
+        totalSegments = (n - 1) / k;
+        toRemain = n - k * totalSegments;
+
+        int top = 0;
+        for (int i = 0; i < n; i++) {
+            cin >> arr[i];
+            top = max(top, arr[i]);
+        }
+
+        int hi = top;
+        int lo = 1;
+
+        while (hi > lo) {
+            int mid = (hi + lo + 1) / 2;
+            if (medAtLeast(mid)) {
+                lo = mid;
+            } else {
+                hi = mid - 1;
+            }
+        }
+
+        cout << lo << endl;
+    }
+
+    return 0;
+}