Create jump-game-ix.cpp

Author: kamyu104

C++/jump-game-ix.cpp

@@ -0,0 +1,25 @@
+// Time:  O(n)
+// Space: O(1)
+
+// dp, mono stack
+class Solution {
+public:
+    long long minCost(vector<int>& nums, vector<int>& costs) {
+        vector<int> stk1, stk2;
+        vector<int64_t> dp(size(nums), numeric_limits<int64_t>::max());
+        dp[0] = 0;
+        for (int i = 0; i < size(nums); ++i) {
+            while (!empty(stk1) && nums[stk1.back()] <= nums[i]) {
+                dp[i] = min(dp[i], dp[stk1.back()] + costs[i]);
+                stk1.pop_back();
+            }
+            stk1.emplace_back(i);
+            while (!empty(stk2) && nums[stk2.back()] > nums[i]) {
+                dp[i] = min(dp[i], dp[stk2.back()] + costs[i]);
+                stk2.pop_back();
+            }
+            stk2.emplace_back(i);
+        }
+        return dp.back();
+    }
+};