[코딩 테스트 문제 + 풀이] Arrays

 

Q. Cyclic Rotation

 

function solution(A, K) {
    let result = new Array(A.length);
    for (let i = 0; i < result.length; i++) {
        result[(i + K) % A.length] = A[i]
    }
    return result;
}


console.log(solution(A:[1, 2, 3, 4, 5], K:2));  // [3, 4, 5, 1, 2]

 

 

 

 

 

Q. Frog River One   // return time when frog can cross 

 

function solution(X, A) {
  let river_positions = new Array(arrayLength:X + 1).fill(value:false);
  for (let time = 0; time < A.length; time++) {
    let pos = A[time];
    if (!river_positions[pos]) {
      river_positions[pos] = true;
      X -= 1;
      if (X === 0) return time;
    }
  } 
  return -1;
}


console.log(solution(X:3, A:[1, 2, 1]));

 

 

 

 

 

 

Q. Max Counter

 

function solution(N, A) {
  let counters = new Array(N).fill(0);
  let start_line = 0;
  let current_max = 0;
  A.forEach(instruction => {
    let index = instruction - 1
    if (instruction > N) start_line = current_max;
    else if (counters[index] < start_line) counters[index] = start_line + 1;
    else counters[index] += 1;
    if (instruction <= N && counters[index] > current_max) current_max = counters[index];
  });
  for (let i = 0; i < counters.length; i++) {
    if (counters[i] < start_line) counters[i] = start_line;
  }
  return counters;
}

console.log(solution(5, [3, 4, 4, 6, 1, 4, 4]));    // [ 3, 2, 2, 4, 2 ]