Nearly every one have used the Multiplication Table. But could you find out the k-th smallest number quickly from the multiplication table?

Given the height m and the length n of a m * n Multiplication Table, and a positive integer k, you need to return the k-th smallest number in this table.

**Example 1:**

**Input:** m = 3, n = 3, k = 5
**Output:Explanation:**
The Multiplication Table:
1 2 3
2 4 6
3 6 9
The 5-th smallest number is 3 (1, 2, 2, 3, 3).

**Example 2:**

**Input:** m = 2, n = 3, k = 6
**Output:Explanation:**
The Multiplication Table:
1 2 3
2 4 6
The 6-th smallest number is 6 (1, 2, 2, 3, 4, 6).

**Note:**

The m and n will be in the range [1, 30000].

The k will be in the range [1, m * n]

**Solution:**

```
class Solution {
public int findKthNumber(int m, int n, int k) {
int left=1,right=m*n;
while(left<right)
{
int mid=left+(right-left)/2;
if(smallest(mid,m,n,k))
right=mid;
else left=mid+1;
}
return left;
}
private boolean smallest(int num,int m,int n,int k)
{
int count=0;
for(int i=1;i<=m;i++)
{
count+=Math.min(num/i,n);
}
return count>=k;
}
}
```

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