Big O exercise

big_o_exercise/bigo.js

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+/*
+1. O(n)
+2. O(log(n))
+3. O(1)
+4. O(n^3)
+5. O(n)
+6. O(log(n))
+7. O(n * log(n))
+8. O(2^n)
+9. O(1)
+10. O(n2)
+*/
+
+//1 O(n)
+function logUpTo(n) {
+    for (var i = 1; i <= n; i++) {
+        console.log(i);
+    }
+}
+
+//2 O(1)
+function logAtMost10(n) {
+    for (var i = 1; i <= Math.min(n, 10); i++) {
+        console.log(i);
+    }
+}
+
+//3 O(n)
+function logAtLeast10(n) {
+    for (var i = 1; i <= Math.max(n, 10); i++) {
+        console.log(i);
+    }
+}
+
+//4 O(log(n))
+function onlyElementsAtEvenIndex(array) {
+    var newArray = Array(Math.ceil(array.length / 2));
+    for (var i = 0; i < array.length; i++) {
+        if (i % 2 === 0) {
+            newArray[i / 2] = array[i];
+        }
+    }
+    return newArray;
+}
+
+//5 O(n^2)
+function subtotals(array) {
+    var subtotalArray = Array(array.length);
+    for (var i = 0; i < array.length; i++) {
+        var subtotal = 0;
+        for (var j = 0; j <= i; j++) {
+            subtotal += array[j];
+        }
+        subtotalArray[i] = subtotal;
+    }
+    return subtotalArray;
+}