Merge Sorted Array

Code:

 

class Solution {
public:
    void merge(int A[], int m, int B[], int n) {
        int i, j, count;
        for(i=0,j=0;i<m&&j<n;i++){
            for(count=0;j<n&&A[i]>=B[j];j++) // count how many smaller than i
                count++;
            if(count>0){ // if there are some elements from B that need to insert into A
                for(int k=m-1;k>i-1;k--) // right-shift
                    A[k+count]=A[k];
                for(int k=0;k<count;k++) // insert
                    A[i+k]=B[j-count+k];
                m += count;
                i += count;
            }
        }
        if(j<n) // splice the rest B elements
            for(int k=0;k<n-j;k++)
                A[m+k]=B[k+j];
    }
};

 

Tricky Solution:

public class Solution {
    public void merge(int A[], int m, int B[], int n) {
        int i = m-1,
            j = n-1,
            k = m+n-1;        
        while(k>=0){
            if(j<0 || (i>=0 && A[i]>B[j]))
                A[k--]=A[i--];
            else
                A[k--]=B[j--];
        }
    }
}