633. Sum of Square Numbers标题

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:

Input: 3
Output: False

public class Solution {
public boolean judgeSquareSum(int c) {
int beg = 0;
int end = (int) Math.sqrt(c);
while (beg <= end) {
int target = beg * beg + end * end;
if (target > c) {
end--;
} else if (target < c) {
beg++;
} else {
return true;
}
}
return false;
}
}