Create 2742-painting-the-walls.java

Author: sujal-goswami

Diff for: java/2742-painting-the-walls.java

@@ -0,0 +1,22 @@
+class Solution {
+    Map<String, Integer> dp;
+    public int paintWalls(int[] cost, int[] time) {
+        int n = cost.length;
+        dp = new HashMap<>();
+        return dfs(0, cost.length, cost, time);
+    }
+    private int dfs(int i, int remain, int[] cost, int[] time){
+        if(remain <= 0)
+            return 0;
+        if(i == cost.length)
+            return (int) 1e9;
+        String s = i + "," + remain;
+        if(dp.containsKey(s))
+            return dp.get(s);
+
+        int paint = cost[i] + dfs(i+1, remain-1-time[i], cost, time);
+        int skip = dfs(i+1, remain, cost, time);
+        dp.put(s, Math.min(paint, skip));
+        return dp.get(s);           
+    }
+}