2 posts tagged with "medium"

/**
 * @param {string} haystack
 * @param {string} needle
 * @return {number}
 */
var strStr = function (haystack, needle) {
  if (haystack.length === 0) {
    if (needle.length === 0) return 0;
    return -1;
  }
  if (haystack.length !== 0) {
    if (needle.length === 0) return 0;
  }

  let index;
  const needleFirstStr = needle[0];

  for (let i = 0; i < haystack.length; i++) {
    if (haystack[i] === needleFirstStr) {
      if (haystack.substring(i, i + needle.length) === needle) {
        index = i;
        break;
      } else {
        index = -1;
      }
    } else {
      index = -1;
    }
  }

  return index;
};

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function (nums) {
  const results = [];

  const permutations = (selected) => {
    // nums의 모든 숫자가 다 쓰였을 경우
    if (selected.length === nums.length) {
      results.push(selected);
      return;
    }

    for (let i = 0; i < nums.length; i++) {
      // 중복인 숫자는 제외하고 추가
      if (!selected.includes(nums[i])) {
        permutations([...selected, nums[i]]);
      }
    }
  };

  permutations([]);

  return results;
};