Fixes

Author: Alexander Belov

src/lib/segment-tree/segment-tree.ts

@@ -1 +1,66 @@
-export class SegmentTree {}
+import { isPowerOfTwo, nearestHighestPowerOfTwoResult } from '@algo-js/core';
+
+export class SegmentTree {
+  /**
+   * Input array
+   *
+   * @type {number[]}
+   * @private
+   */
+  private input: number[] = [];
+
+  /**
+   * Operation function
+   *
+   * @type {function}
+   * @private
+   */
+  private operation: () => {};
+
+  /**
+   * Fallback value for non-intersect intervals
+   *
+   * @type {function}
+   * @private
+   */
+  private fallbackValue: number = 0;
+
+  /**
+   * Tree instance
+   *
+   * @type {number[]}
+   */
+  private tree: number[] = null;
+
+  /**
+   * @param {number[]} input
+   * @param {function} operation
+   * @param {number} fallbackValue
+   */
+  constructor(input: number[], operation: () => {}, fallbackValue: number = 0) {
+    this.input = input;
+    this.operation = operation;
+    this.fallbackValue = fallbackValue;
+
+    this.tree = this.createTree();
+  }
+
+  private createTree(): number[] {
+    let segmentTreeArrayLength;
+    const inputArrayLength = this.input.length;
+
+    let treeArrayLength = inputArrayLength;
+
+    if (!isPowerOfTwo(inputArrayLength)) {
+      // If original array length is not a power of two then we need to find
+      // next number that is a power of two and use it to calculate
+      // tree array size. This is happens because we need to fill empty children
+      // in perfect binary tree with nulls.And those nulls need extra space.
+      treeArrayLength = nearestHighestPowerOfTwoResult(inputArrayLength + 1);
+    }
+
+    segmentTreeArrayLength = 2 * treeArrayLength - 1;
+
+    return new Array(segmentTreeArrayLength).fill(null);
+  }
+}

tslint.json

@@ -9,26 +9,26 @@
     /* tslint-immutable rules */
     // Recommended built-in rules
     "no-var-keyword": true,
-    "no-parameter-reassignment": true,
+    "no-parameter-reassignment": false,
     "typedef": [true, "call-signature"],
 
     // Immutability rules
-    "readonly-keyword": true,
+    "readonly-keyword": false,
     "readonly-array": false,
     "no-let": false,
-    "no-object-mutation": true,
+    "no-object-mutation": false,
     "no-delete": false,
-    "no-method-signature": true,
+    "no-method-signature": false,
 
     // Functional style rules
     "no-this": false,
     "no-class": false,
-    "no-mixed-interface": true,
+    "no-mixed-interface": false,
     "no-expression-statement": [
-      true,
+      false,
       { "ignore-prefix": ["console.", "process.exit"] }
     ],
-    "no-if-statement": true,
+    "no-if-statement": false,
     "no-bitwise": false,
     "no-unused-variable": false,
     "no-unused-expression": false,

yarn.lock

@@ -2,6 +2,11 @@
 # yarn lockfile v1
 
 
+"@algo-js/core@^1.0.21":
+  version "1.0.21"
+  resolved "https://registry.yarnpkg.com/@algo-js/core/-/core-1.0.21.tgz#6aa375a0768ad6159be33e44b88644ee8cae1bab"
+  integrity sha512-a2nv+LawY1hJHr+RhThVvjQfaeCen0oACvAM0EDzNuCTwgTYhwje9WvELmRUo8T61O+lXDIs0WXlV7TkmjM66g==
+
 "@ava/babel-plugin-throws-helper@^3.0.0":
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/@ava/babel-plugin-throws-helper/-/babel-plugin-throws-helper-3.0.0.tgz#2c933ec22da0c4ce1fc5369f2b95452c70420586"