Dp2

Problem1.java

@@ -0,0 +1,20 @@
+class Problem1 {
+    public int minCost(int[][] costs) {
+        int m = costs.length;
+        int n = costs[0].length;
+
+        int[][] dp = new int[m][n];
+
+        dp[m-1][0] = costs[m-1][0];
+        dp[m-1][1] = costs[m-1][1];
+        dp[m-1][2] = costs[m-1][2];
+
+        for(int i = m - 2; i >= 0; i--) {
+            dp[i][0] = costs[i][0] + Math.min(dp[i+1][1], dp[i+1][2]);
+            dp[i][1] = costs[i][1] + Math.min(dp[i+1][0], dp[i+1][2]);
+            dp[i][2] = costs[i][2] + Math.min(dp[i+1][0], dp[i+1][1]);
+        }
+
+        return Math.min(dp[0][0], Math.min(dp[0][1], dp[0][2]));
+    }
+}

Problem2.java

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+class Problem2 {
+    public int change(int amount, int[] coins) {
+        int m = coins.length;
+        int n = amount;
+
+        int[][] dp = new int[m+1][n+1];
+        dp[0][0] = 1;
+
+        for(int i=1; i<=m; i++){
+            for(int j=0; j<=n; j++){
+                if(j < coins[i-1]){
+                    dp[i][j] = dp[i-1][j];
+                }else{
+                    dp[i][j] = dp[i-1][j] +  dp[i][j - coins[i-1]];
+                }
+            }
+        }
+
+        return dp[m][n];
+    }
+}