Data commit

Task/Binary-search/Jsish/binary-search.jsish

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+/**
+   Binary search, in Jsish, based on Javascript entry
+   Tectonics: jsish -u -time true -verbose true binarySearch.jsi
+*/
+function binarySearchIterative(haystack, needle) {
+    var mid, low = 0, high = haystack.length - 1;
+
+    while (low <= high) {
+        mid = Math.floor((low + high) / 2);
+        if (haystack[mid] > needle) {
+            high = mid - 1;
+        } else if (haystack[mid] < needle) {
+            low = mid + 1;
+        } else {
+            return mid;
+        }
+    }
+    return null;
+}
+
+/* recursive */
+function binarySearchRecursive(haystack, needle, low, high) {
+    if (high < low) { return null; }
+
+    var mid = Math.floor((low + high) / 2);
+
+    if (haystack[mid] > needle) {
+        return binarySearchRecursive(haystack, needle, low, mid - 1);
+    }
+    if (haystack[mid] < needle) {
+        return binarySearchRecursive(haystack, needle, mid + 1, high);
+    }
+    return mid;
+}
+
+/* Testing and timing */
+if (Interp.conf('unitTest') > 0) {
+    var arr = [];
+    for (var i = -5000; i <= 5000; i++) { arr.push(i); }
+
+    assert(arr.length == 10001);
+    assert(binarySearchIterative(arr, 0) == 5000);
+    assert(binarySearchRecursive(arr, 0, 0, arr.length - 1) == 5000);
+
+    assert(binarySearchIterative(arr, 5000) == 10000);
+    assert(binarySearchRecursive(arr, -5000, 0, arr.length - 1) == 0);
+
+    assert(binarySearchIterative(arr, -5001) == null);
+
+    puts('--Time 100 passes--');
+    puts('Iterative:', Util.times(function() { binarySearchIterative(arr, 42); }, 100), 'µs');
+    puts('Recursive:', Util.times(function() { binarySearchRecursive(arr, 42, 0, arr.length - 1); }, 100), 'µs');
+}