g0301_0400.s0367_valid_perfect_square.Solution Maven / Gradle / Ivy
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Java Solution for LeetCode algorithm problems, continually updating
package g0301_0400.s0367_valid_perfect_square;
// #Easy #Math #Binary_Search
public class Solution {
public boolean isPerfectSquare(int num) {
if (num == 0) {
// If num is 0 return false
return false;
}
// long datatype can holds huge number.
long start = 0;
long end = num;
long mid = 0;
while (start <= end) {
// until start is lesser or equal to end do this
// Finding middle value
mid = start + (end - start) / 2;
if (mid * mid == num) {
// if mid*mid == num return true
return true;
} else if (mid * mid < num) {
// if num is greater than mid*mid then make start = mid + 1
start = mid + 1;
} else if (mid * mid > num) {
// if num is lesser than mid*mid then make end = mid - 1
end = mid - 1;
}
}
return false;
}
}