0633. Sum of Square Numbers - kumaeki/LeetCode GitHub Wiki
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
遍历.
class Solution {
public boolean judgeSquareSum(int c) {
double limit = Math.sqrt(c);
for(int i = 0; i <= limit; i++){
double d = Math.sqrt(c - i * i);
if(d % 1 == 0) return true;
}
return false;
}
}滑动窗口
class Solution {
public boolean judgeSquareSum(int c) {
int i =0 , j = (int)Math.sqrt(c);
while(i<=j){
int powsum = i * i + j * j;
if(powsum < c)
i++;
else if (powsum > c)
j--;
else
return true;
}
return false;
}
}