g0001_0100.s0069_sqrtx.Solution Maven / Gradle / Ivy

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Java Solution for LeetCode algorithm problems, continually updating

There is a newer version: 1.24

package g0001_0100.s0069_sqrtx;

// #Easy #Top_Interview_Questions #Math #Binary_Search #Binary_Search_I_Day_4
// #2022_06_18_Time_2_ms_(79.35%)_Space_41.8_MB_(23.51%)

public class Solution {
    public int mySqrt(int x) {
        int start = 1;
        int end = x / 2;
        int sqrt = start + (end - start) / 2;
        if (x == 0) {
            return 0;
        }
        while (start <= end) {
            if (sqrt == x / sqrt) {
                return sqrt;
            } else if (sqrt > x / sqrt) {
                end = sqrt - 1;
            } else if (sqrt < x / sqrt) {
                start = sqrt + 1;
            }
            sqrt = start + (end - start) / 2;
        }
        if (sqrt > x / sqrt) {
            return sqrt - 1;
        } else {
            return sqrt;
        }
    }
}