[unn04012] 25.01.02 (codingTestStd#10)

* 배열 자르기, 기초

* 배열 회전시키기, 기초

* 제일 작은 수 제거하기, 중급

* 나누어 떨어지는 숫자 배열, 중급

* 행렬의 곱셈, 심화

Author: unn04012

unn04012/array/Array_of_divisible_numbers.js

@@ -0,0 +1,12 @@
+function solution(arr, divisor) {
+  const answer = [];
+
+  for (const e of arr) {
+    if (e % divisor === 0) answer.push(e);
+  }
+  if (answer.length === 0) answer.push(-1);
+
+  return answer.sort((a, b) => a - b);
+}
+
+console.log(solution([5, 9, 7, 10], 5));

unn04012/array/Matrix_multiplication.js

@@ -0,0 +1,31 @@
+function solution(arr1, arr2) {
+  const n = arr1.length;
+  const m = arr2[0].length;
+
+  const answer = Array.from({ length: n }, () => Array(m).fill(0));
+
+  for (let i = 0; i < n; i++) {
+    for (let j = 0; j < m; j++) {
+      const result = arr1[i].reduce((acc, cur, idx) => acc + cur * arr2[idx][j], 0);
+
+      answer[i][j] = result;
+    }
+  }
+
+  return answer;
+}
+
+console.log(
+  solution(
+    [
+      [2, 3, 2],
+      [4, 2, 4],
+      [3, 1, 4],
+    ],
+    [
+      [5, 4, 3],
+      [2, 4, 1],
+      [3, 1, 1],
+    ]
+  )
+);

unn04012/array/arr_rotate.js

@@ -0,0 +1,19 @@
+function solution(numbers, direction) {
+  const answer = [];
+
+  if (direction === 'right') {
+    for (let i = 0; i < numbers.length - 1; i++) {
+      answer[i + 1] = numbers[i];
+    }
+    answer[0] = numbers[numbers.length - 1];
+  } else {
+    for (let i = numbers.length - 1; i >= 1; i--) {
+      answer[i - 1] = numbers[i];
+    }
+    answer[numbers.length - 1] = numbers[0];
+  }
+
+  return answer;
+}
+
+console.log(solution([4, 455, 6, 4, -1, 45, 6], 'left'));

unn04012/array/cut_array.js

@@ -0,0 +1,9 @@
+function solution(numbers, num1, num2) {
+  const answer = [];
+
+  for (let i = num1; i <= num2; i++) answer.push(numbers[i]);
+
+  return answer;
+}
+
+console.log(solution([1, 2, 3, 4, 5], 1, 3));

unn04012/array/delete_min_num.js

@@ -0,0 +1,10 @@
+function solution(arr) {
+  const answer = [];
+  const minNum = Math.min(...arr);
+
+  for (const e of arr) {
+    if (e === minNum) continue;
+    answer.push(e);
+  }
+  return answer.length ? answer : [-1];
+}