minn rewards code updated.

Author: Partho Biswas

algoexpert.io/python/Min_Rewards.py

@@ -19,8 +19,39 @@ def minRewards(score):
 
 # Solution #2
 # O(n) time | O(n) space
-def minRewards(score):
-    pass
+def minRewards(scores):
+    rewards = [1 for _ in scores]
+    localMinIdxs = getLocalMinIdxs(scores)
+    for localMinIdx in localMinIdxs:
+        expandFromLocalMinIdx(localMinIdx, scores, rewards)
+    return sum(rewards)
+
+
+def getLocalMinIdxs(array):
+    if len(array) == 1:
+        return [0]
+    localMinIdxs = []
+    for i in range(len(array)):
+        if i == 0  and array[i] < array[i + 1]:
+            localMinIdxs.append(i)
+        if i == len(array) - 1 and array[i] < array[i - 1]:
+            localMinIdxs.append(i)
+        if i == 0 or  i == len(array) - 1:
+            continue
+        if array[i] < array[i + 1] and array[i] < array[i - 1]:
+            localMinIdxs.append(i)
+    return localMinIdxs
+
+
+def expandFromLocalMinIdx(localMinIdx, scores, rewards):
+    leftIdx = localMinIdx - 1
+    while leftIdx >= 0 and scores[leftIdx] > scores[leftIdx + 1]:
+        rewards[leftIdx] = max(rewards[leftIdx], rewards[leftIdx + 1] + 1)
+        leftIdx -= 1
+    rightIdx = localMinIdx + 1
+    while rightIdx < len(scores) and scores[rightIdx] > scores[rightIdx - 1]:
+        rewards[rightIdx] = rewards[rightIdx - 1] + 1
+        rightIdx += 1