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Author: BrandonTang89

Other_Tasks/CF2043_C_Sums_on_Segments.cpp

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+#pragma GCC optimize("Ofast")
+#pragma GCC optimize("unroll-loops")
+#include <bits/stdc++.h>
+using namespace std;
+
+typedef long long ll;
+#define fast_cin()                    \
+    ios_base::sync_with_stdio(false); \
+    cin.tie(NULL);                    \
+    cout.tie(NULL);
+
+set<ll> sums;
+
+void processHeights(vector<ll> &h) {
+    int n = h.size();
+    ll maxSeen = h[n - 1];
+    ll minSeen = h[n - 1];
+
+    ll biggestDown = 0;
+    ll biggestUp = 0;
+
+    for (int i = n - 2; i >= 0; i--) {
+        ll down = minSeen - h[i];
+        ll up = maxSeen - h[i];
+
+        biggestDown = min(biggestDown, down);
+        biggestUp = max(biggestUp, up);
+
+        minSeen = min(minSeen, h[i]);
+        maxSeen = max(maxSeen, h[i]);
+    }
+
+    for (ll i = biggestDown; i <= biggestUp; i++) {
+        sums.insert(i);
+    }
+}
+
+int main() {
+    fast_cin();
+    int tc;
+    cin >> tc;
+    while (tc--) {
+        int n;
+        vector<ll> rightActions, leftActions;
+        vector<ll> right;
+        vector<ll> left;
+        sums.clear();
+
+        cin >> n;
+
+        vector<ll> arr(n);
+        ll x = 0;
+        int xidx = 0;
+        for (int i = 0; i < n; i++) {
+            cin >> arr[i];
+            if (arr[i] > 1 || arr[i] < -1) {
+                xidx = i;
+            }
+        }
+        x = arr[xidx];
+
+        leftActions = vector<ll>(arr.begin(), arr.begin() + xidx);
+        rightActions = vector<ll>(arr.begin() + xidx + 1, arr.end());
+
+        ll sumLeft = 0;
+        for (int i = 0; i < leftActions.size(); i++) {
+            sumLeft += leftActions[i];
+        }
+
+        left.assign(leftActions.size() + 1, 0);
+        left[0] = -sumLeft;
+        for (int i = 1; i < left.size(); i++) {
+            left[i] = left[i - 1] + leftActions[i - 1];
+        }
+        assert(left.back() == 0);
+
+        right.assign(rightActions.size() + 1, 0);
+        right[0] = 0;
+        for (int i = 1; i < right.size(); i++) {
+            right[i] = right[i - 1] + rightActions[i - 1];
+        }
+
+        processHeights(left);
+        processHeights(right);
+
+        ll maxLeft = *max_element(left.begin(), left.end());
+        ll minLeft = *min_element(left.begin(), left.end());
+        ll maxRight = *max_element(right.begin(), right.end());
+        ll minRight = *min_element(right.begin(), right.end());
+
+        ll up = maxRight - minLeft;
+        for (int i = 0; i <= up; i++) {
+            sums.insert(i + x);
+        }
+
+        ll down = minRight - maxLeft;
+        for (int i = down; i <= 0; i++) {
+            sums.insert(i + x);
+        }
+
+        cout << sums.size() << endl;
+        for (auto i : sums) {
+            cout << i << " ";
+        }
+        cout << endl;
+    }
+    return 0;
+}