Sidebar

Recent changes
Trace: • algorithm

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
algorithm:algorithm [2016/06/07 13:12] – ledyxalgorithm:algorithm [2022/10/24 15:32] (current) – ledyx
Line 3: Line 3:
 {{tag>Algorithm}} {{tag>Algorithm}}
  
-= 마방진 (Magic Square) = += Recursion = 
-  * 홀수만 처리 가능! +[[recursion|참조]]
-<sxh java ; title:Language : Java> +
-int size = 5; +
- +
-int[][] arr = new int[size][size]; +
-  +
-int middle = size/2; +
- +
-int i=0, j=middle; +
-for(int num=1 ; num<=size*size ; num++) { +
- arr[i][j] = num; +
-  +
- //행 감소 +
- i--; +
- if(i < 0) +
- i = size-1; +
-  +
- //열 증가 +
- j = (++j)%size; +
- //아래 표현과 같다. +
- /*j++; +
- if(j >= size) +
- j = 0;*/ +
- +
- //배수이면 행은 1 증가, 열은 그대로 +
- if(num%size == 0) { +
- i = (i+2)%size; +
- j--; +
- if(j < 0) +
- j = size-1; +
- } +
-} +
-</sxh>+
  
 = Sort = = Sort =
Line 48: Line 16:
  
 = Search = = Search =
-== 이진 탐색 (Binary Search) == +== Binary Search (이진 탐색) == 
-  * 일반적인 구현 +[[binary search|참조]]
-<sxh java> +
- public static int binarySearch(int[] arr, int target) { +
- int left = 0; +
- int right = arr.length - 1; +
- int mid = 0; +
-  +
- while(left <= right) { +
- mid = (left + right) / 2; +
-  +
- if(arr[mid] < target) +
- left = mid + 1; +
- else if (arr[mid] > target) +
- right = mid - 1; +
- else +
- return mid; +
- } +
-  +
- return Integer.MIN_VALUE; +
- } +
-</sxh> +
- +
- +
-  * 재귀적 구현 +
-<sxh java> +
- public static int binarySearchRecursive(int[] arr, int target, int left, int right) { +
- if(left > right) +
- return Integer.MIN_VALUE; +
-  +
- int mid = (left + right) / 2; +
- if(arr[mid] < target) +
- return binarySearchRecursive(arr, target, left + 1, right); +
- else if (arr[mid] > target) +
- return binarySearchRecursive(arr, target, left, right - 1); +
- else +
- return mid; +
- } +
-</sxh> +
- +
- +
-  * A ＜ X ≤ B 조건을 검색. (반환값이 index+1 이므로) +
-<sxh java> +
- public static int binarySearch(ArrayList<Integer> list, int target) { +
- +
- int left = 0; +
- int right = list.size() - 1; +
- int middle = 0; +
-  +
- while(left <= right) { +
-  +
- middle = (left + right) / 2; +
-  +
- if(target < list.get(middle)) { +
- right = middle - 1; +
- } +
- else { +
- left = middle + 1; +
- } +
- +
  
- if(list.get(middle) <= target && middle < list.size() - 1) { 
- if(target < list.get(middle + 1)) { 
- return list.get(list.size() > middle + 1 ? middle + 1 : list.size() - 1); 
- } 
- } 
- } 
-  
- return -1; 
- } 
-</sxh> 
algorithm/algorithm.1465305120.txt.gz · Last modified: (external edit)