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lc_135_candy.cpp

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+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+class Solution {
+    static vector<int> get_upstairs_lengths(vector<int>& ratings) {
+        vector<int> upstairs(ratings.size(), 1);
+        for (int i = 1; i < ratings.size(); i++) {
+            if (ratings[i] > ratings[i - 1]) {
+                upstairs[i] = upstairs[i - 1] + 1;
+            }
+        }
+        return upstairs;
+    }
+
+    static vector<int> get_downstairs_lengths(vector<int>& ratings) {
+        vector<int> downstairs(ratings.size(), 1);
+        for (int i = ratings.size() - 2; i >= 0; i--) {
+            if (ratings[i] > ratings[i + 1]) {
+                downstairs[i] = downstairs[i + 1] + 1;
+            }
+        }
+        return downstairs;
+    }
+
+public:
+    int candy(vector<int>& ratings) {
+        vector<int> upstairs = get_upstairs_lengths(ratings);
+        vector<int> downstairs = get_downstairs_lengths(ratings);
+        int ans = 0;
+        for (int i = 0; i < ratings.size(); i++) {
+            ans += max(upstairs[i], downstairs[i]);
+        }
+        return ans;
+    }
+};
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    size_t ratings_amount;
+    cin >> ratings_amount;
+    vector<int> ratings(ratings_amount);
+    for (int i = 0; i < ratings_amount; i++) {
+        cin >> ratings[i];
+    }
+    Solution solution;
+    cout << solution.candy(ratings) << endl;
+
+    return 0;
+}