Data commit

Task/Display-a-linear-combination/Groovy/display-a-linear-combination.groovy

@@ -0,0 +1,44 @@
+class LinearCombination {
+    private static String linearCombo(int[] c) {
+        StringBuilder sb = new StringBuilder()
+        for (int i = 0; i < c.length; ++i) {
+            if (c[i] == 0) continue
+            String op
+            if (c[i] < 0 && sb.length() == 0) {
+                op = "-"
+            } else if (c[i] < 0) {
+                op = " - "
+            } else if (c[i] > 0 && sb.length() == 0) {
+                op = ""
+            } else {
+                op = " + "
+            }
+            int av = Math.abs(c[i])
+            String coeff = av == 1 ? "" : "" + av + "*"
+            sb.append(op).append(coeff).append("e(").append(i + 1).append(')')
+        }
+        if (sb.length() == 0) {
+            return "0"
+        }
+        return sb.toString()
+    }
+
+    static void main(String[] args) {
+        int[][] combos = [
+                [1, 2, 3],
+                [0, 1, 2, 3],
+                [1, 0, 3, 4],
+                [1, 2, 0],
+                [0, 0, 0],
+                [0],
+                [1, 1, 1],
+                [-1, -1, -1],
+                [-1, -2, 0, -3],
+                [-1]
+        ]
+
+        for (int[] c : combos) {
+            printf("%-15s  ->  %s\n", Arrays.toString(c), linearCombo(c))
+        }
+    }
+}