add Costumes solution

Author: jakovmitrovski

medium300/Costumes.java

@@ -0,0 +1,42 @@
+package medium300;
+
+public class Costumes {
+
+    int[][] dp;
+    int[][] dist;
+    int n;
+
+    int res(int ind, int mask) {
+
+        if (mask == ((1 << n) - 1))
+            return dist[ind][0];
+
+        if (dp[ind][mask] != -1)
+            return dp[ind][mask];
+
+        int ret = 1 << 20;
+
+        for (int i = 0; i < n; i++)
+            if ((mask & (1 << i)) == 0)
+                ret = Math.min(ret, dist[ind][i] + res(i, mask | (1 << i)));
+        return dp[ind][mask] = ret;
+    }
+
+    public int minimumPath(int[] x, int[] y) {
+        n = x.length;
+        dist = new int[20][20];
+        dp = new int[18][1 << 18];
+        for (int i = 0; i < x.length; i++)
+            for (int j = i + 1; j < y.length; j++) {
+                int cost = Math.abs(x[i] - x[j]) + Math.abs(y[i] - y[j]);
+                dist[i][j] = cost;
+                dist[j][i] = cost;
+            }
+
+        for (int i = 0; i < 18; i++)
+            for (int j = 0; j < 1 << 18; j++)
+                dp[i][j] = -1;
+
+        return res(0, 1);
+    }
+}