Create 135. Candy

Author: khushi3004

135. Candy

@@ -0,0 +1,94 @@
+class Solution {
+    public int candy(int[] ratings) {
+        int candies = 0, n = ratings.length;
+        int[] left = new int[n];
+        int[] right = new int[n];
+        
+        Arrays.fill(left, 1);
+        Arrays.fill(right, 1);
+        
+        //Left relative array
+        for(int i = 1; i < n; i++) {
+            //If current index rating > previous ; give extra candies
+            if(ratings[i] > ratings[i-1]) left[i] = left[i-1] + 1;
+        }
+        
+        //Right relative array
+        for(int i = n-2; i >= 0; i--) {
+            if(ratings[i] > ratings[i+1]) right[i] = right[i+1] +1;
+        }
+        
+       //Merge both the sides
+        for(int i = 0; i < n; i++) {
+            candies = candies + Math.max(left[i], right[i]);
+        }
+        
+        return candies;
+    }
+}
+
+
+class Solution {
+    public int candy(int[] ratings) {
+        int[] candies = new int[ratings.length];
+        Arrays.fill(candies, 1);
+        
+        for(int i = 1; i < ratings.length; i++) {
+            if(ratings[i] > ratings[i - 1])
+                candies[i] = candies[i - 1] + 1;
+        }
+        for(int i = ratings.length - 2; i >= 0; i--) {
+            if(ratings[i] > ratings[i + 1])
+                candies[i] = Math.max(candies[i], candies[i+1] +1);
+        }
+        int total = 0; 
+        for(int candy : candies) 
+            total+=candy;
+        
+        return total;
+    }
+}
+
+class Solution {
+    public int candy(int[] ratings) {
+        if(ratings.length <= 1) return ratings.length;
+        int candies = 0;
+        int up = 0, down = 0; 
+        int prevSlope = 0;
+        
+        for(int i = 1; i < ratings.length; i++) {
+            //If increasing then 1; if decreasing then -1; if equal then 0.
+            int currSlope = (ratings[i] > ratings[i-1]) ? 1 
+                : (ratings[i] < ratings[i-1] ? -1 : 0);
+            //                                       _
+            //If mountain is changing. \_ || \/ ||  /
+            if((prevSlope < 0 && currSlope >= 0) || (prevSlope > 0 && currSlope == 0)) {  
+                candies = candies + sum(up) + sum(down) + (Math.max(up, down));
+                System.out.println(up + " "+ down + " " +candies);
+                up = 0; 
+                down = 0;
+            }
+            
+            //Add in up/down if slope is increasing or decreasing respectively. 
+            //If it is a plain, add a candy as it is the base case.
+            if(currSlope > 0) {
+                up++;
+            }
+            else if(currSlope < 0) {
+                down++;
+            }
+            else {
+                candies++;
+            }
+            
+            prevSlope = currSlope;
+        } 
+        System.out.println(up + " "+ down + " "+ candies);
+        candies = candies + sum(up) + sum(down) + (Math.max(up, down) + 1);
+        return candies;
+    }
+    
+    int sum(int n) {
+        return (n * (n + 1)) / 2;
+    }
+}