add (programmers - level2 3문제, level 3, 4 각 1문제): js 풀이

programmers/level2/[3차] n진수 게임.js

@@ -0,0 +1,16 @@
+function solution(n, t, m, p) {
+  let answer = '';
+  const arr = [];
+
+  for (let i = 0; i < t * m; i++) {
+      arr.push(...i.toString(n).split(''));
+  }
+
+  for (let i = 0; i < t * m; i++) {
+      if (i % m === 0) {
+          answer += arr[i + p - 1]
+      }
+  }
+
+  return answer.toUpperCase();
+}

programmers/level2/오픈채팅방.js

@@ -0,0 +1,25 @@
+function solution(record) {
+  const log = [];
+  const users = {};
+
+  record.forEach(r => {
+    const [action, uid, nickname] = r.split(" ");
+
+    if (action === "Enter") {
+      users[uid] = nickname;
+      log.push({ uid, action });
+    } else if (action === "Leave") {
+      log.push({ uid, action });
+    } else if (action === "Change") {
+      users[uid] = nickname;
+    }
+  });
+
+  const answer = log.map(({ uid, action }) => {
+    return `${users[uid]}님이 ${
+      action === "Enter" ? "들어왔습니다." : "나갔습니다."
+    }`;
+  });
+
+  return answer;
+}

programmers/level2/주차 요금 계산.js

@@ -0,0 +1,67 @@
+function solution(fees, records) {
+  let answer = [];
+
+  const IN_LIST = {};
+  const OUT_LIST = {};
+
+  records.forEach(record => {
+    const [time, number, action] = record.split(" ");
+
+    if (action === "IN") {
+      if (IN_LIST[number]) {
+        IN_LIST[number].push(time);
+      } else {
+        IN_LIST[number] = [time];
+      }
+    } else if (action === "OUT") {
+      if (OUT_LIST[number]) {
+        OUT_LIST[number].push(time);
+      } else {
+        OUT_LIST[number] = [time];
+      }
+    }
+  });
+
+  const [base, baseCharge, unitTime, unitCharge] = fees;
+
+  for (const item of Object.entries(IN_LIST).sort(
+    ([a], [b]) => Number(a) - Number(b)
+  )) {
+    const [number, inList] = item;
+    const outList = OUT_LIST[number];
+
+    let fee = 0;
+    let totalMinutes = 0;
+    inList.forEach((inTime, idx) => {
+      const [inHour, inMinutes] = inTime.split(":").map(Number);
+      const [outHour, outMinutes] =
+        outList && outList.length > idx
+          ? outList[idx].split(":").map(Number)
+          : [23, 59];
+
+      let calcHour = outHour;
+      let calcMinutes = outMinutes;
+
+      if (calcMinutes < inMinutes) {
+        calcMinutes = calcMinutes + 60 - inMinutes;
+        calcHour = calcHour - 1;
+      } else {
+        calcMinutes = calcMinutes - inMinutes;
+      }
+
+      calcHour = calcHour - inHour;
+      totalMinutes += calcHour * 60 + calcMinutes;
+    });
+
+    if (base < totalMinutes) {
+      fee =
+        baseCharge + Math.ceil((totalMinutes - base) / unitTime) * unitCharge;
+    } else {
+      fee = baseCharge;
+    }
+
+    answer.push(fee);
+  }
+
+  return answer;
+}

programmers/level3/N으로 표현.js

@@ -0,0 +1,24 @@
+function solution(N, number) {
+  const dp = Array.from({ length: 9 }, (v, i) => new Set());
+
+  for (let i = 1; i < 9; i++) {
+    dp[i].add("1".repeat(i) * N);
+    for (let j = 1; j < i; j++) {
+      for (const num1 of dp[j]) {
+        for (const num2 of dp[i - j]) {
+          dp[i].add(num1 + num2);
+          dp[i].add(num1 - num2);
+          dp[i].add(num1 * num2);
+          dp[i].add(num1 / num2);
+        }
+      }
+    }
+
+    if (dp[i].has(number)) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+solution(2, 11);

programmers/level4/사칙연산.js

@@ -0,0 +1,43 @@
+function solution(arr) {
+  const len = Math.ceil(arr.length / 2);
+  const MAX_DP = Array.from({ length: len }, (v, i) =>
+    Array.from({ length: len }, (v, i) => -Infinity)
+  );
+  const MIN_DP = Array.from({ length: len }, (v, i) =>
+    Array.from({ length: len }, (v, i) => Infinity)
+  );
+
+  for (let i = 0; i < len; i++) {
+    MAX_DP[i][i] = Number(arr[i * 2]);
+    MIN_DP[i][i] = Number(arr[i * 2]);
+  }
+
+  for (let cnt = 1; cnt < len; cnt++) {
+    for (let i = 0; i < len - cnt; i++) {
+      const j = i + cnt;
+      for (let k = i; k < j; k++) {
+        if (arr[k * 2 + 1] === "+") {
+          MAX_DP[i][j] = Math.max(
+            MAX_DP[i][j],
+            MAX_DP[i][k] + MAX_DP[k + 1][j]
+          );
+          MIN_DP[i][j] = Math.min(
+            MIN_DP[i][j],
+            MIN_DP[i][k] + MIN_DP[k + 1][j]
+          );
+        } else {
+          MAX_DP[i][j] = Math.max(
+            MAX_DP[i][j],
+            MAX_DP[i][k] - MIN_DP[k + 1][j]
+          );
+          MIN_DP[i][j] = Math.min(
+            MIN_DP[i][j],
+            MIN_DP[i][k] - MAX_DP[k + 1][j]
+          );
+        }
+      }
+    }
+  }
+
+  return MAX_DP[0][len - 1];
+}