07.18: sort, greedy(도서관)

baekjoon/1461.js

@@ -0,0 +1,53 @@
+// 도서관 : 정렬, 그리디
+const input = require("fs")
+  .readFileSync("/dev/stdin")
+  .toString()
+  .trim()
+  .split("\n")
+  .map((v) => v.split(" ").map((v) => Number(v)));
+const [bookNum, maxCarry] = input.shift();
+const booksCoord = input.shift().sort((a, b) => a - b);
+const negative = booksCoord.filter((v) => v < 0);
+const positive = booksCoord.filter((v) => v > 0).reverse();
+const negativeGroup = splitGroup(negative);
+const positiveGroup = splitGroup(positive);
+let answer = 0;
+
+function splitGroup(arr) {
+  const group = [];
+  let start = 0;
+  for (let i = 0; i < arr.length; i++) {
+    if (i % maxCarry === maxCarry - 1) {
+      group.push(arr.slice(start, i + 1));
+      start = i + 1;
+    }
+  }
+
+  if (arr.length !== start) {
+    group.push(arr.slice(start, arr.length));
+  }
+  return group.reverse();
+}
+
+function solve(arr) {
+  let answer = 0;
+  let prev;
+  for (let i = 0; i < arr.length; i++) {
+    const curr = arr[i];
+    // 끝이면 돌아올 필요 없음
+    if (i !== 0) {
+      answer += prev;
+    }
+    answer += Math.abs(curr.at(0));
+    prev = Math.abs(curr.at(0));
+  }
+  return answer;
+}
+
+answer += solve(positiveGroup);
+answer += solve(negativeGroup);
+// add smaller end-point
+if (positive.length && negative.length) {
+  answer += Math.min(positive[0], Math.abs(negative[0]));
+}
+console.log(answer);