633 Sum of Square Numbers
Problem
Given a non-negative integer c, your task is to decide whether there're two integers a and b such that a2 + b2 = c.
Example 1:
Input: 5
Output: True
Explanation: 1 * 1 + 2 * 2 = 5
Example 2:
Solutions
class Solution {
public boolean judgeSquareSum(int c) {
HashSet<Long> nums = new HashSet<>();
for (int i = 0; i <= Math.sqrt(c); i ++) {
nums.add((long)i*i);
if (nums.contains((long)(c - i*i))) {
return true;
}
}
return false;
}
}