Create maximum-fruits-harvested-after-at-most-k-steps.cpp

Author: kamyu104

C++/maximum-fruits-harvested-after-at-most-k-steps.cpp

@@ -0,0 +1,31 @@
+// Time:  O(n)
+// Space: O(n)
+
+class Solution {
+public:
+    int maxTotalFruits(vector<vector<int>>& fruits, int startPos, int k) {
+        const int max_pos = max(startPos, fruits.back()[0]);
+        vector<int> cnt(max_pos + 1);
+        for (const auto& x : fruits) {
+            cnt[x[0]] += x[1];
+        }
+        vector<int> prefix(1);
+        for (int i = 0; i < size(cnt); ++i) {
+            prefix.emplace_back(prefix.back() + cnt[i]);
+        }
+        int result = 0;
+        for (int left_dist = 0; left_dist <= min(startPos, k); ++left_dist) {
+            const int right_dist = max(k - 2 * left_dist, 0);
+            const int left = startPos - left_dist;
+            const int right = min(startPos + right_dist, max_pos);
+            result = max(result, prefix[right + 1] - prefix[left]);
+        }
+        for (int right_dist = 0; right_dist <= min(max_pos - startPos, k); ++right_dist) {
+            const int left_dist = max(k - 2 * right_dist, 0);
+            const int left = max(startPos - left_dist, 0);
+            const int right = startPos + right_dist;
+            result = max(result, prefix[right + 1] - prefix[left]);
+        }
+        return result;
+    }
+};