first commit

+node_modules
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+{
+  "name": "hw",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "scripts": {
+    "start": "node src/index.js"
+  },
+  "dependencies": {
+    "fs-extra": "^6.0.1"
+  }
+}

+const { assign } = require("./tools");
+
+function searchBlock(state, process) {
+  let candidates = state
+    .map((block, key) => assign(block, { key }))
+    .filter(block => block.id == -1 && block.size >= process.size);
+
+  candidates.sort((blockX, blockY) => {
+    const x = blockY.size;
+    const y = blockY.size;
+    if (x < y) return -1;
+    else if (x > y) return 1;
+    else return 0;
+  });
+
+  return candidates.length != 0 ? candidates[0].key : -1;
+}
+
+const getCapacity = state =>
+  state
+    .filter(block => block.id == -1)
+    .reduce((capacity, block) => capacity + block.size, 0);
+
+function insert(state, process, target) {
+  const bound = target.from + process.size;
+
+  return target.size == process.size
+    ? [assign(target, { id: process.id })]
+    : [
+        assign(target, { id: process.id, size: process.size }),
+        assign(target, { size: target.size - process.size })
+      ];
+}
+
+function compact(state) {
+  const size = getCapacity(state);
+  return [...state.filter(block => block.id != -1), { id: -1, size }];
+}
+
+function allocate(state, process) {
+  const capacity = getCapacity(state);
+
+  if (capacity < process.size) {
+    throw new Error("OUT OF MEMORY");
+  }
+
+  let idx = searchBlock(state, process);
+
+  if (idx == -1) {
+    state = compact(state);
+    idx = searchBlock(state, process);
+  }
+
+  const target = state[idx];
+  const nextState = [
+    ...state.slice(0, idx),
+    ...insert(state, process, target),
+    ...state.slice(idx + 1)
+  ];
+  const offset = idx;
+  return nextState;
+}
+
+module.exports = allocate;

+const { assign } = require("./tools");
+
+function coalscence(state) {
+  const last = xs => xs[xs.length - 1];
+  const join = (state, block) => [
+    ...state.slice(0, -1),
+    { id: -1, size: block.size + last(state).size }
+  ];
+
+  const [firstBlock, ...restBlock] = state;
+
+  let idx = -1;
+  let offset = 0;
+  const nextState = restBlock.reduce(
+    (nextState, block) => {
+      offset += block.size;
+      if (last(nextState).id == -1 && block.id == -1) {
+        idx = offset;
+        return join(nextState, block);
+      } else {
+        return [...nextState, block];
+      }
+    },
+    [firstBlock]
+  );
+  return nextState;
+}
+
+function free(state, pid) {
+  const nextState = state.map(
+    block => (block.id == pid ? assign(block, { id: -1 }) : block)
+  );
+  return coalscence(nextState);
+}
+
+module.exports = free;

+const allocate = require("./allocate");
+const free = require("./free");
+const { printMemory, printStatus } = require("./print");
+const parse = require("./parse");
+const fs = require("fs");
+
+function run(request, state) {
+  const { type, payload } = request;
+  const method = type == "allocate" ? allocate : free;
+  const head =
+    type == "allocate"
+      ? `Request ${payload.id}: ${payload.size}K`
+      : `Free Request ${payload}`;
+
+  const nextState = method(state, payload);
+  printMemory(nextState);
+  printStatus(nextState);
+  return nextState;
+}
+
+try {
+  const raw = String(fs.readFileSync("test.txt"));
+  const { MAX_CAPACITY, requests } = parse(raw);
+  const init = { id: -1, size: MAX_CAPACITY };
+  let state = [init];
+
+  for (const request of requests) state = run(request, state);
+} catch (e) {
+  console.error(e);
+}

+function buffer2(xs) {
+  
+  const ys = xs.filter((_, i) => !(i % 2));
+  const zs = xs.filter((_, i) => i % 2);
+  let ws = [];
+
+  for (let i = 0; i < ys.length; ++i) {
+    ws.push([ys[i], zs[i]]);
+  }
+  return ws;
+}
+
+function parse(raw) {
+  const [MAX_CAPACITY, rawRequests] = raw.split(/\r?\n/);
+  const requests = buffer2(rawRequests.split(" ").map(v => parseInt(v))).map(
+    ([id, size]) =>
+      size
+        ? { type: "allocate", payload: { id, size } }
+        : { type: "free", payload: id }
+  );
+  return { MAX_CAPACITY, requests }
+}
+
+module.exports = parse;
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+function printMemory(state) {
+  let addr = 0;
+  console.log(`----------------`);
+  for (const block of state) {
+    if (block.id == -1) {
+      console.log(`|     free     |`);
+    } else {
+      const pid = `${block.id}`.padStart(6, " ");
+      console.log(`| pid: ${pid}  |`);
+    }
+    const size = `${block.size}`.padStart(5, " ");
+    const from = `${addr}`.padStart(5, " ");
+    addr += block.size;
+    const to = `${addr}`.padStart(5, " ");
+    console.log(`|              |`);
+    console.log(`| size: ${size}K |`);
+    console.log(`| from: ${from}K |`);
+    console.log(`| to:   ${to}K |`);
+    console.log(`----------------`);
+  }
+}
+
+function printStatus(state) {
+  const freeBlocks = state.filter(block => block.id == -1);
+  const count = freeBlocks.length;
+  const totalFree = freeBlocks.reduce((z, block) => z + block.size, 0);
+  console.log(`${totalFree}K free`);
+  console.log(`${count} block(s)`);
+  console.log(`Average: ${Math.round(totalFree / count)}\n`);
+}
+
+module.exports = { printMemory, printStatus };

+const assign = (origin, diff) => Object.assign({}, origin, diff);
+
+module.exports = { assign };

+256
+1 64 2 64 3 32 4 16 1 0 3 0 5 32 2 0
\ No newline at end of file

+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+fs-extra@^6.0.1:
+  version "6.0.1"
+  resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-6.0.1.tgz#8abc128f7946e310135ddc93b98bddb410e7a34b"
+  dependencies:
+    graceful-fs "^4.1.2"
+    jsonfile "^4.0.0"
+    universalify "^0.1.0"
+
+graceful-fs@^4.1.2, graceful-fs@^4.1.6:
+  version "4.1.11"
+  resolved "https://registry.yarnpkg.com/graceful-fs/-/graceful-fs-4.1.11.tgz#0e8bdfe4d1ddb8854d64e04ea7c00e2a026e5658"
+
+jsonfile@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/jsonfile/-/jsonfile-4.0.0.tgz#8771aae0799b64076b76640fca058f9c10e33ecb"
+  optionalDependencies:
+    graceful-fs "^4.1.6"
+
+universalify@^0.1.0:
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/universalify/-/universalify-0.1.1.tgz#fa71badd4437af4c148841e3b3b165f9e9e590b7"