[oh-chaeyeon] 25.01.02 (codingTestStd#7)

* 배열 자르기 / 기초

* 배열 원소의 길이 / 기초

* 배열 회전시키기 / 기초

* 중복된 숫자 개수 / 기초

* 제일 작은 수 제거하기 / 중급

* 행렬의 덧셈 / 중급

* 나누어 떨어지는 숫자 배열 / 중급

* 행렬의 곱셈 / 심화

* 교점에 별 만들기 / 심화

* n^2 배열 자르기 / 심화

Author: oh-chaeyeon

oh-chaeyeon/.gitkeep

@@ -0,0 +1,9 @@
+function solution(n, left, right) {
+  const answer = [];
+  for (let k = left; k <= right; k++) {
+    const i = Math.floor(k / n);
+    const j = k % n;
+    answer.push(Math.max(i, j) + 1);
+  }
+  return answer;
+}

oh-chaeyeon/1주차_배열/n^2_배열_자르기.js

@@ -0,0 +1,39 @@
+function solution(line) {
+  const points = [];
+
+  for (let i = 0; i < line.length; i++) {
+    for (let j = i + 1; j < line.length; j++) {
+      const [A1, B1, C1] = line[i];
+      const [A2, B2, C2] = line[j];
+
+      const denominator = A1 * B2 - A2 * B1;
+
+      if (denominator !== 0) {
+        const x = (B1 * C2 - B2 * C1) / denominator;
+        const y = (A2 * C1 - A1 * C2) / denominator;
+
+        if (Number.isInteger(x) && Number.isInteger(y)) {
+          points.push([x, y]);
+        }
+      }
+    }
+  }
+
+  const xs = points.map((point) => point[0]);
+  const ys = points.map((point) => point[1]);
+
+  const minX = Math.min(...xs);
+  const maxX = Math.max(...xs);
+  const minY = Math.min(...ys);
+  const maxY = Math.max(...ys);
+
+  const width = maxX - minX + 1;
+  const height = maxY - minY + 1;
+  const grid = Array.from({ length: height }, () => Array(width).fill("."));
+
+  for (const [x, y] of points) {
+    grid[maxY - y][x - minX] = "*";
+  }
+
+  return grid.map((row) => row.join(""));
+}

oh-chaeyeon/1주차_배열/교점에_별_만들기.js

@@ -0,0 +1,5 @@
+function solution(arr, divisor) {
+  var answer = arr.filter((num) => num % divisor === 0);
+  if (answer.length === 0) return [-1];
+  return answer.sort((a, b) => a - b);
+}

oh-chaeyeon/1주차_배열/나누어_떨어지는_숫자_배열.js

@@ -0,0 +1,3 @@
+function solution(strlist) {
+  return strlist.map((str) => str.length);
+}

oh-chaeyeon/1주차_배열/배열_원소의_길이.js

@@ -0,0 +1,4 @@
+function solution(numbers, num1, num2) {
+  var answer = numbers.slice(num1, num2 + 1);
+  return answer;
+}

oh-chaeyeon/1주차_배열/배열_자르기.js

@@ -0,0 +1,10 @@
+function solution(numbers, direction) {
+  if (direction === "right") {
+    return [
+      numbers[numbers.length - 1],
+      ...numbers.slice(0, numbers.length - 1),
+    ];
+  } else if (direction === "left") {
+    return [...numbers.slice(1), numbers[0]];
+  }
+}

oh-chaeyeon/1주차_배열/배열_회전시키기.js

@@ -0,0 +1,5 @@
+function solution(arr) {
+  const min = Math.min(...arr);
+  var answer = arr.filter((num) => num !== min);
+  return answer.length === 0 ? [-1] : answer;
+}

oh-chaeyeon/1주차_배열/제일_작은_수_제거하기.js

@@ -0,0 +1,6 @@
+function solution(array, n) {
+  var answer = array.reduce((count, num) => {
+    return num === n ? count + 1 : count;
+  }, 0);
+  return answer;
+}

oh-chaeyeon/1주차_배열/중복된_숫자_개수.js

@@ -0,0 +1,17 @@
+function solution(arr1, arr2) {
+  const rowsA = arr1.length;
+  const colsA = arr1[0].length;
+  const colsB = arr2[0].length;
+
+  const result = Array.from({ length: rowsA }, () => Array(colsB).fill(0));
+
+  // 행렬 곱셈
+  for (let i = 0; i < rowsA; i++) {
+    for (let j = 0; j < colsB; j++) {
+      for (let k = 0; k < colsA; k++) {
+        result[i][j] += arr1[i][k] * arr2[k][j];
+      }
+    }
+  }
+  return result;
+}