# Leetcode 633. Sum of Square Numbers

Aug 25, 2021

[medium]

Given a non-negative integer `c`

, decide whether there're two integers `a`

and `b`

such that `a2 + b2 = c`

.

**Example 1:**

**Input:** c = 5

**Output:** true

**Explanation:** 1 * 1 + 2 * 2 = 5

**Example 2:**

**Input:** c = 3

**Output:** false

**Example 3:**

**Input:** c = 4

**Output:** true

**Example 4:**

**Input:** c = 2

**Output:** true

**Example 5:**

**Input:** c = 1

**Output:** true

**Constraints:**

`0 <= c <= 231 - 1`

[Java]

- use two pointer to closer the target number
- if we could not find a result for the nunmber c, return false