2.1.2 Insertion sort decreasing order
Java:
public class Solution {
public int[] insertSortDec(int[] arr){ for(int j = 1; j<arr.length; j++){ int i = j-1; int key = arr[j]; while(i>=0 && arr[i] < key){ arr[i+1] = arr[i]; i--; } arr[i+1] = key; } return arr; }}
2.3-5
Java
public class Solution{ public boolean binarySearch(int[] arr, int val, int left, int right){ if(left > right){ return false; } int mid = (left+right)/2; int midVal = arr[mid]; if(midVal == val){ return true; }else if(midVal > val){ return binarySearch(arr, midVal, left,mid-1 ); }else{ return binarySearch(arr, midVal, mid+1, right); } }}
2:3 - 7
Sort A[] --- nlgn
Two pointers check sum A --- n
In total, nlgn