add: Candies

Author: Jer3myYu

java/Greedy/Candies.java

@@ -0,0 +1,29 @@
+import java.util.Arrays;
+
+public class Candies {
+    public int candies(int[] ratings) {
+        int n = ratings.length;
+        // Ensure each child starts with 1 candy.
+        int[] candies = new int[n];
+        Arrays.fill(candies, 1);
+        // First pass: for each child, ensure the child has more candies  
+        // than their left-side neighbor if the current child's rating is 
+        // higher.
+        for (int i = 1; i < n; i++) {
+            if (ratings[i] > ratings[i - 1]) {
+                candies[i] = candies[i - 1] + 1;
+            }
+        }
+        // Second pass: for each child, ensure the child has more candies 
+        // than their right-side neighbor if the current child's rating is 
+        // higher.
+        for (int i = n - 2; i >= 0; i--) {
+            if (ratings[i] > ratings[i + 1]) {
+                // If the current child already has more candies than their 
+                // right-side neighbor, keep the higher amount.
+                candies[i] = Math.max(candies[i], candies[i + 1] + 1);
+            }
+        }
+        return Arrays.stream(candies).sum();
+    }
+}