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367.java
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367.java
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sample 0 ms submission
/*
* @lc app=leetcode id=367 lang=java
*
* [367] Valid Perfect Square
*/
class Solution {
public boolean isPerfectSquare(int num) {
if (num == 1) {
return true;
}
long start = 1, end = num;
while (start < end - 1) {
long middle = start + (end - start) / 2;
long temp = middle * middle;
if (temp == (long)num) {
return true;
} else if (temp > (long)num) {
end = middle;
} else {
start = middle;
}
}
return start * start == num || end * end == num;
}
}
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sample 31424 kb submission
class Solution {
public boolean isPerfectSquare(int num) {
int low=1, high=num, mid;
while(low<=high){
mid=low+(high-low)/2;
if(num/mid < mid){
high=mid-1;
}
else{
if(mid*mid==num){
return true;
}
low=mid+1;
}
}
return false;
}
}
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