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int SequenceSearch(int a[], int n, int key)
{
    int i=0;
    while(i < n && a[i] != key){
        i++;
    }
    return i==n ? -1 : i;
}

int BinarySearch(int a[], int n, int key)
{
    int low, high, mid;
    low = 0;
    high = n-1;
    while(low <= high) {
        mid = low + (high - low)/2;
        if (a[mid] == key) {
            return mid;
        } else if (a[mid] > key){
            high = mid -1;
        } else {
            low = mid + 1;
        }
    }
    return -1;
}