Merge pull request chipbk10#98 from chipbk10/DP

Solve Problem 213 & 1388

Author: chipbk10

src/dp/decision_making/Problem1388_PizzaWith3NSlices.java

@@ -0,0 +1,21 @@
+package dp.decision_making;
+
+public class Problem1388_PizzaWith3NSlices {
+
+    public int maxSizeSlices(int[] A) {
+        int n = A.length, x = 3, m = n/x;
+        return Math.max(findMax(A, 0, n-2, m), findMax(A, 1, n-1, m));
+    }
+
+    private int findMax(int[] A, int lo, int hi, int m) {
+        int[][] dp = new int[hi-lo+1][m+1];
+        for (int i = 0; i <= hi-lo; i++) {
+            for (int k = 1; k <= m; k++) {
+                int max2 = (i >= 2) ? dp[i-2][k-1] : 0;
+                int max1 = (i >= 1) ? dp[i-1][k] : 0;
+                dp[i][k] = Math.max(max1, max2 + A[i+lo]);
+            }
+        }
+        return dp[hi-lo][m];
+    }
+}

src/dp/decision_making/Problem213_HouseRobberII.java

@@ -0,0 +1,20 @@
+package dp.decision_making;
+
+public class Problem213_HouseRobberII {
+
+    public int rob(int[] A) {
+        int n = A.length;
+        if (n == 1) return A[0];
+        return Math.max(findMax(A, 0, n-2), findMax(A, 1, n-1));
+    }
+
+    public int findMax(int[] A, int lo, int hi) {
+        int max1 = 0, max2 = 0, max = 0;
+        for (int i = lo; i <= hi; i++) {
+            max = Math.max(max2 + A[i], max1);
+            max2 = max1;
+            max1 = max;
+        }
+        return max;
+    }
+}